RURAL  TEXT-BOOK 
SERIES 


UC-NRLF 


THE 

FEEDING  OF 
ANIMALS 


JORDAN 

L.  H.  BAILEY 

EDITOR 


A6R1C. 
LIBRARY 


IRural  UeiMBoofc  Series 

EDITED  BY  L.  H.  BAILEY 


THE  FEEDING  OF  ANIMALS 


TTbe  IRural  UeiWBoofe  Series 

EDITED  BY  L.  H.  BAILEY 

Carleton,  THE  SMALL  GRAINS. 

B.     M.     Duggar,     PLANT     PHYSIOLOGY,     with 

special  reference  to  Plant  Production. 
/.  F.  Duggar,  SOUTHERN  FIELD  CROPS. 
Gay,  THE  BREEDS  OF  LIVE-STOCK. 
Gay,    THE     PRINCIPLES    AND     PRACTICE     OF 

JUDGING  LIVE-STOCK. 
Goff,    THE    PRINCIPLES    OF   PLANT    CULTURE, 

Revised. 

Harper,  ANIMAL  HUSBANDRY  FOR  SCHOOLS. 
Harris    and    Stewart,      THE     PRINCIPLES     OF 

AGRONOMY. 

Hitchcock,  A  TEXT-BOOK  OF  GRASSES. 
Jeffery,  TEXT-BOOK  OF  LAND  DRAINAGE. 
Jordan,  THE  FEEDING  OF  ANIMALS.  Revised. 
Livingston,  FIELD  CROP  PRODUCTION. 
Lyon,    Pippin    and     Buckman,     SOILS — THEIR 

PROPERTIES  AND  MANAGEMENT. 
Mann,  BEGINNINGS  IN  AGRICULTURE. 
Montgomery,  THE  CORN  CROPS. 
Piper,   FORAGE   PLANTS  AND  THEIR  CULTURE. 
Warren,  ELEMENTS  OF  AGRICULTURE. 
Warren,  FARM  MANAGEMENT. 
Wheeler,  MANURES  AND  FERTILIZERS. 
White,  PRINCIPLES  OF  FLORICULTURE. 
Widtsoe,  PRINCIPLES  OF  IRRIGATION  PRACTICE. 


THE 
FEEDING  OF  ANIMALS 


BY 

WHITMAN  HOWARD  JORDAN 

DIRECTOR  OF  THE  NEW  YORK  AGRICULTURAL 
EXPERIMENT  STATION,  GENEVA 


REVISED  EDITION 


J^etogorfe 

THE  MACMILLAN  COMPANY 
1917 

Aft  rights  reserved 


COPYRIGHT,  1901  AND  1917 
BY  THE   MACMILLAN   COMPANY 


Set  up  and  electrotyped  June,  1901 

Reprinted  September,  1903;  February,  1905;  October,  1906 
February,  1908;    January  and  July,    1909;    October,   1910 

February,  1912;  January,  1914 
New  and  Revised  Edition,  January,  1917 


Jteonnt  Pleasant  Press 

J.  Horace  McFarl 

Harrisburg,  Pa. 


TABLE  OF  CONTENTS 

PARTNI.    THE  PRINCIPLES  OF  FEEDING 
CHAPTER  I 

PAGES 

INTRODUCTION:  MAN'S  RELATION  TO  ANIMAL  LIFE    .       .         3-8 
The  conditions  and  problems  involved  in  feeding  animals. 

CHAPTER  II 
THE  RELATIONS  OF  PLANT  AND  ANIMAL  LIFE    .       .       .       9-11 

Origin  of  animal  foods,  1;  The  plant  stores  energy,  2; 
Plant  substance  a  source  of  animal  substance,  3;  The 
plant  a  source  of  animal  heat,  4;  Food  a  source  of  motive 
power,  5. 

CHAPTER  III 

THE  CHEMICAL  ELEMENTS  INVOLVED  IN  ANIMAL  NUTRI- 
TION               12-25 

Chemical  elements  involved  in  animal  growth,  6. 
The  Elements  and  Their  Sources:  Carbon,  7;  Carbon  in 
the  air,  8;  Oxygen,  9;  Uses  of  oxygen,  10;  Hydrogen, 
11;  Nitrogen,  12;  Supply  of  nitrogen,  13;  Uses  of 
nitrogen,  14;  Argon,  15;  Sulfur,  16;  Phosphorus,  17; 
Chlorine,  18;  Iodine,  '19;  Potassium,  20;  Sodium,  21; 
Calcium,  22;  Iron,  23.  Proportions  of  the  Elements  in 
Plants  and  Animals:  Elements  in  plants,  24;  Elements 
in  plant  ash,  25;  Elements  in  animals,  26;  Ash  elements 
in  animals,  27;  Classes  of  matter,  28;  Combustion  does 
not  destroy  matter,  29;  Relation  of  combustible  to 
incombustible  substance,  30;  Organic  and  inorganic 
classes,  31. 

(v) 


357295 


vi  CONTENTS 

CHAPTER  IV 
THE  COMPOUNDS  OF  ANIMAL  NUTRITION      ....     26-46 

The  classes  of  compounds,  32;  Distribution  of  ele- 
ments, 33.  Water:  Measurement  of  water-content,  34; 
Hygroscopic  water,  35;  Physiological  water,  36;  Water 
hi  living  plants,  37;  Sap  or  plant  juice,  38;  Proportion 
of  water  in  plants,  39;  Effect  of  stage  of  growth  on 
water-content,  40;  Influence  of  soil  moisture,  41;  Supply 
of  water  to  plants,  42;  Water  in  feeding-stuffs,  43;  Con- 
ditions affecting  water-content  of  feeds,  44;  Relation  of 
water  to  preservation  of  cattle  foods,  45;  Water  hi  the 
animal,  46;  Variations  of  water-content  of  animal 
bodies,  47.  Ash:  Mineral  compounds  in  the  ash  of  plants 
and  animals,  48;  Rearrangement  of  ash  elements  during 
ignition,  49;  The  ash  compounds  of  plants,  50;  Varia- 
tions of  plant  ash,  51 ;  Variations  of  ash  due  to  species, 
52;  The  distribution  of  mineral  compounds  in  the  differ- 
ent parts  of  the  plant,  53;  Influence  of  manufacturing 
processes  on  the  ash  constitutents,  54;  The  mineral 
compounds  of  animal  bodies,  55;  The  distribution  of 
inorganic  compounds  in  the  animal  body,  56;  Ash  ele- 
ments in  the  soft  tissues,  57;  Ash  elements  in  the  blood, 
58. 

CHAPTER  V 

THE  COMPOUNDS  OP  ANIMAL  NUTRITION,   CONTINUED — 

THE  NITROGEN  COMPOUNDS 47-67 

The  importance  of  protein,  59.  Protein:  How  protein 
is  determined,  60;  So-called  proteins  greatly  unlike,  61; 
Classification  of  proteins,  62;  The  true  proteins,  63; 
Ultimate  composition  of  proteins,  64;  Familiar  exam- 
ples of  proteins,  65.  Simple  Proteins:  The  albumins, 
66;  The  globulins,  67;  Plant  globulins,  68;  Animal  glob- 
ulins, 69;  Glutenins,  70;  Alcohol-soluble  proteins,  71; 
Albuminoids,  72;  Histones,  protamines,  73.  Conjugated 
Proteins:  Nucleo-proteins,  74;  Gly  co-proteins,  75; 
Phospho-proteins,  76;  Haemoglobin,  77;  Lecitho-pro- 
teins,  78.  Derived  Proteins:  1.  Primary  Protein  Deriva- 
tives: Proteins  and  metaproteins,  79;  Coagulated  pro- 


CONTENTS  vii 

teins,  80.  2.  Secondary  Protein  Derivatives:  Proteoses,  PAGES 
peptones,  81;  Important  properties  of  the  proteins,  82; 
The  unlike  constitution  of  the  various  proteins,  83; 
Cleavage  products  of  the  proteins,  84.  Nitrogen  Com- 
pounds That  Are  Non-Proteins:  Ammo-acids  and 
amides,  85;  Extractives,  86. 

CHAPTER  VI 

THE  COMPOUNDS  OF  ANIMAL  NUTRITION,  CONCLUDED — 

CARBOHYDRATES,  ACIDS,  FATS,  AND  OILS       .       .       .     68-86 

Elementary  composition  of  the  non-nitrogenous 
compounds,  87;  Classification  of  non-nitrogenous  com- 
pounds, 88;  The  carbohydrates,  89;  Classification  of 
carbohydrates  according  to  structure,  90;  The  mono- 
saccharides  or  simple  sugars,  91;  Dextrose,  92;  Levulose, 
93;  Galactose,  94;  The  pentoses,  95;  Di-saccharides, 
96;  Saccharose,  97;  Maltose,  98;  Lactose,  99;  The  sugars 
as  a  class,  100;  Other  more  complex  poly-saccharides, 
101;  The  starches,  102;  Glycogen,  103;  The  pentosans, 
104;  Galactans,  mannans,  levulans,  dextrans,  105;  The 
pectin  bodies,  106;  Dextrin,  107;  Cellulose,  108;  The 
acids,  109;  Fats  and  oils,  110;  Fats  or  oils  in  grains  and 
seeds,  111;  Nature  and  kinds  of  fats,  112;  Physical 
properties  of  the  fats  and  oils,  113;  Milk-fat,  114; 
Fatty  acids,  115;  Ether-extracts,  116;  Lecithins,  117; 
Enzyms,  anti-bodies,  hormones,  vitamines  (accessories), 
118. 

CHAPTER  VII 

THE  DIGESTION  OF  FOOD 87-122 

Digestion  vs.  assimilation,  119;  General  changes  in 
food  through  digestion,  120.  Ferments:  Definition  of  fer- 
ments, 121;  Organized  ferments,  122;  Structure  and 
distribution  of  organized  ferments,  123;  Conditions  of 
growth  of  organized  ferments,  124;  Results  of  fermenta- 
tion, 125;  Manner  of  action  of  ferments,  126;  Bacteria  in 
the  digestive  tract,  127;  Unorganized  ferments,  128; 
Enzyms  and  their  action,  129.  The  Alimentary  Canal: 


Vlll  CONTENTS 

Parts  of  the  alimentary  canal,  130.  The  Mouth:  Masti-  PAGES 
cation,  131;  The  teeth,  132;  The  saliva,  133;  Origin  of 
saliva,  134;  Properties  and  office  of  saliva,  135;  Quan- 
tity of  saliva  excreted,  136.  The  Stomach:  The  rumi- 
nant stomach,  137;  Esophageal  groove,  138;  The  rumen, 
139;  The  reticulum,  140;  Rumination,  141 ;  The  omasum, 
142;  The  abomasum,  143;  The  gastric  juice,  144;  Arti- 
ficial digestion,  145;  Changes  in  stomach  digestion,  146; 
Hydrochloric  acid  essential  in  stomach  digestion,  147; 
The  stomachs  of  the  horse  and  pig,  148.  The  Intestines: 
Form  and  length  of  intestines,  149;  Food  in  the  small 
intestine,  150;  The  bile,  151;  Functions  of  bile,  152; 
The  pancreatic  juice,  153;  The  enzyms  of  the  pan- 
creatic juice,  154;  Steapsin,  155;  Amylopsin,  156; 
Intestinal  juices,  157;  Intestinal  bacteria,  158;  Effects 
of  intestinal  fermentations,  159;  Stimuli  to  digestion, 
160;  Secretins,  161;  The  psychic  factor,  162;  Digestion  of 
food  as  a  whole,  163;  Stomach  digestion,  164;  Digestion 
in  intestines,  165;  Digestive  fluids  act  together,  166; 
Action  of  intestinal  juices,  167;  Summary  of  changes 
in  digestion,  168.  Absorption  of  Food:  Function  of 
lacteals  and  blood  vessels  in  absorption,  169;  Manner  of 
food  absorption,  170;  Changes  in  the  walls  of  the  intes- 
tinal tract,  171 ;  Place  of  maximum  absorption  of  food, 
172.  The  Feces:  Constituents  of  feces,  173;  The  feces 
not  wholly  undigested  food,  174.  The  Relation  of  the  Dif- 
ferent Food  Compounds  to  the  Digestive  Processes:  Digesti- 
bility of  the  proteins,  175;  Digestibility  of  the  carbo- 
hydrates, 176;  Starches  unlike  in  rate  of  digestibility, 
177;  Digestibility  of  cellulose  and  gums,  178;  Digesti- 
bility of  the  fats,  179.  Factors  Which  May  Influence 
Digestion:  Meaning  of  "digestibility,"  180. 


CHAPTER  VIII 

CONDITIONS  INFLUENCING  DIGESTION 123-137 

Palatableness,  181;  Influence  of  quantity  of  ration, 
182;  Effect  of  drying  fodders,  183;  Influence  of  the  con- 
ditions and  methods  of  preserving  fodders,  184;  Influ- 


CONTENTS  ix 

ence  of  the  stage  of  growth  of  the  plant,  185;  Influence  PAQES 
of  methods  of  preparation  of  food,  186;  Wetting  food, 
187;  Cooking  foods,  188;  Influence  of  grinding  foods, 
189;  Effect  of  common  salt,  190;  Influence  of  frequency 
of  feeding  and  watering  animals,  191;  Influence  of 
season  and  storage,  192;  Influence  of  the  combination 
of  food  nutrients,  193;  Influence  of  work,  194;  Influence 
of  species,  breed,  age,  and  individuality,  195;  Lower 
digestibility  with  horses  for  eoarse  foods,  196;  Deter- 
mination of  digestibility,  197;  The  inaccuracies  of 
digestion  coefficients,  198. 

CHAPTER  IX 
THE  DISTRIBUTION  AND  USE  OF  THE  DIGESTED  FOOD    .    138-150 

The  blood,  199;  The  blood  corpuscles,  200;  The  blood 
plasma,  201;  The  heart,  202;  Circulation  of  blood,  203; 
The  lungs,  204;  Object  of  respiration,  205;  The  use  of 
food,  206;  Nutrients  are  oxidized,  207;  Oxidases,  208; 
Proteins  not  wholly  oxided,  209;  Rate  of  oxidation  of 
nutrients,  210.  Elimination  of  Wastes:  Elimination  of 
urea,  211;  Elimination  of  carbon  dioxid,  212;  Elimina- 
tion of  water,  213.  The  Liver:  Regulation  of  carbo- 
hydrate use,  214. 

CHAPTER  X 
THE  FUNCTIONS  OF  THE  NUTRIENTS      .  151-196 

General  uses  of  food,  215;  Uses  of  energy,  216;  Func- 
tions of  water,  217.  Functions  of  the  Mineral  Elements: 
Relation  of  mineral  elements  to  vital  processes,  218; 
Relation  of  mineral  elements  to  animal  structure,  219; 
Distribution  of  mineral  elements  in  animal  body,  220; 
Relation  of  mineral  elements  to  elimination  of  waste 
products,  221 ;  Relation  of  mineral  elements  to  a  proper 
equilibrium  between  the  acids  and  bases  of  the  animal 
body,  222;  Relation  of  mineral  elements  to  osmosis, 
223;  Relation  of  mineral  elements  to  muscular  control, 
224;  Relation  of  mineral  elements  to  tissue  development, 
225;  General  considerations,  226;  Supply  of  mineral  ele- 


CONTENTS 

ments,  227;  Relative  efficiency  of  different  phosphorus 
compounds,  228.  Functions  of  Protein:  Proteins  as 
tissue-formers,  229;  Protein  as  a  source  of  fats,  230; 
Protein  as  a  source  of  energy,  231.  Functions  of  Car- 
bohydrates: Carbohydrates  the  chief  source  of  energy, 
232;  Proportion  of  ration  used  as  fuel,  233;  Fats  from 
carbohydrates,  234.  Functions  of  the  Fats  and  Oils: 
Fats  and  carbohydrates  similar  in  function,  235.  Food 
as  a  Source  of  Energy:  Work  performed  by  the  animal 
organism,  236;  Work  requires  the  expenditure  of  energy, 
237;  The  animal  organism  does  not  originate  energy, 
238;  The  nature  of  energy,  239;  Transformations  of 
energy  though  the  use  of  machinery,  240;  The  horse  a 
machine,  241;  Measurement  of  energy,  242;  Determina- 
tion of  energy  units  in  feeding-stuffs,  243;  Metabolizable 
energy,  244;  Loss  of  food  energy  in  feces,  245;  Loss  of 
food  energy  in  urine,  246;  Loss  of  food  energy  in  gases, 
247;  Recent  determinations  of  metabolizable  energy, 
248;  Distribution  of  losses  of  food  energy,  249;  Influence 
of  size  of  ration  on  losses  of  methane,  250;  Influence 
of  size  of  ration  on  losses  in  the  undigested  residue,  251 ; 
Influence  of  individuality  on  energy  losses,  252; 
Estimates  of  metabolizable  energy  on  the  basis  of 
digestible  organic  matter,  253;  Comparison  of  metaboliz- 
able energy  in  coarse  fodders  and  grains,  254;  Net 
energy,  255;  Work  of  mastication,  256;  Difference  in 
total  energy  use  with  different  rations,  257;  The  work  of 
digestion,  258;  Total  energy  expended  in  feed  consump- 
tion, 259;  Calculation  of  net  energy  value,  260;  Net 
energy  of  various  feeds,  261 J  Computing  net  energy 
values  of  feeding-stuffs,  262;  Estimation  of  produc- 
tion values  proposed  by  Armsby,  263.  Energy  Rela- 
tions.— Heat  Regulation:  Relation  of  protein  to 
muscular  activity,  264;  Energy  chiefly  from  carbohy- 
drates and  5ats,  265;  Heat  regulation,  266;  Animal  heat  a 
secondary  or  waste  product,  267;  The  critical  tempera- 
ture, 268.  The  Nutritive  Inter-Relation  of  the  Food  Com- 
pounds and  the  Need  of  Combining  These  in  the  Ration: 
Protein  physiologically  necessary,  269;  Carbohydrates 


CONTENTS  xi 

physiologically  economical,  270;  Protein-sparers,  271;  PAQES 
Nutritive  value  of  the  gums,  272;  Relative  importance 
of  the  nitrogen  compounds  of  feeding-stuffs,  273;  Rela- 
tive nutritive  efficiency  of  the  true  proteins,  274;  A 
single  amino  acid  a  limiting  factor,  275;  Nutritive  value 
of  the  gelatinoids,  276;  Synthesis  in  the  animal  of  phos- 
phorus-bearing proteins,  277;  The  function  of  certain 
unidentified  bodies,  278;  Relation  of  production 
values  to  profit  from  feeding  animals,  279. 

CHAPTER  XI 
LAWS  OF  NUTRITION  .       .       .       ...       .       .       .  197-200 

CHAPTER  XII 

SOURCES  OF  KNOWLEDGE  .        .       .      .*_ .  ...     .V      .       .201-215 

Conclusions  from  feeding  practice,  289;  Practical 
feeding  experiments,  290;  Inconclusiveness  of  ordinary 
feeding  experiments,  291;  Chemical  and  physiological 
studies,  292;  More  accurate  methods  of  investigation 
than  practical  feeding  tests,  293;  Studies  of  food 
sources  of  animal  fats,  294;  The  respiration  apparatus, 
295;  Determination  of  energy  values,  296;  Calculation 
of  the  energy  value  of  a  ration,  297;  Energy  value  of 
digested  nutrients,  298;  Measurement  of  food  com- 
bustion, 299;  Respiration  calorimeter,  300;  Study  of 
the  efficiency  of  individual  proteins,  301. 


PART  II.    THE  PRACTICE  OF  FEEDING 

CHAPTER  XIII 

CATTLE  FOODS — NATURAL  PRODUCTS 219-241 

Classification  of   cattle  foods,   302.     Forage  Foods:     . 
Classes  of  forage  crops,  303;  Green  vs.  dried  fodders; 
conditions  of  drying,  304;  Effect  of  drying  fodders, 


Xli  CONTENTS 

305;  Losses  through  curing  fodders,  306;  The  harvest- 
ing  of  forage  crops,  307;  Maximum  yield  of  forage  crops 
at  maturity,  308;  Value  of  crops  not  proportional  to 
yield,  309;  Age  decreases  digestibility,  310;  Maize  unlike 
other  grasses,  311;  Alfalfa,  312.  Silage:  Nature  of  the 
changes  in  the  silo,  313;  losses  in  silo,  314;  Corn  an 
important  silo  crop,  315;  Extent  of  loss  in  the  silo,  316; 
Necessary  loss  in  silo,  317;  Financial  importance  of 
silo  losses,  318;  Ensiling  vs.  field-curing,  319;  Crops  for 
silage,  320;  Construction  of  silo,  321;  Filling  the  silo, 
322;  Mature  corn  desirable  for  silage,  323;  Cutting  and 
shredding  ensilage  material,  324;  Rate  of  filling  silo, 
325.  The  Straws:  326.  Roots  and  Tubers:  327.  Grains 
and  Seeds:  328.  Storage  of  grain,  329. 


CHAPTER  XIV 
CATTLE  FOODS — COMMERCIAL  FEEDING-STUFFS   .       .       .  242-271 

Classes  of  commercial  by-product  feeding-stuffs,  330; 
Wheat  offals,  331;  Structure  of  the  wheat  grain,  332; 
The  milling  of  wheat,  333;  Composition  of  milling  prod- 
ucts of  wheat,  334;  Milling  processes  compared,  335; 
Screenings,  336;  Residues  from  breakfast  foods,  337; 
The  oat  grain,  oat  hulls,  338;  Oat  clippings,  339;  Barley 
feed,  340;  Hominy  feed,  341;  Brewers'  grains;  malt- 
sprouts,  342;  Residues  from  starch  and  glucose  manu- 
facture, 343;  Structure  of  the  maize  kernel,  344;  Manu- 
facture of  starch,  345;  Residues  from  the  manufacture  of 
beet-sugar,  346;  The  oil  meals  in  general,  347;  Methods 
of  extracting  oils,  348;  Cottonseed  meal,  349;  Cotton- 
seed hulls,  350;  Extraction  of  oil  from  the  cottonseed 
kernels,  351;  Composition  of  cottonseed  oil  by-prod- 
ucts, 352;  Linseed  oil  (oil  meal),  353;  Extraction  of 
Unseed  oil,  354;  Old  process  vs.  new  process  linseed 
meal,  355.  Chemical  Distinctions  in  Cattle  Foods: 
Coarse  foods  vs.  grains  and  grain  products,  356;  Classi- 
fication of  feeds  according  to  the  proportion  of  nutrients, 
357;  Misleading  terms  for  feeding-stuffs,  358;  Classi- 
fication of  feeding-stuffs,  359.  Foods  of  Animal  Origin: 


CONTENTS  xiii 

360.    Milk,  361;  Milk  of  several  breeds,  362;  Dairy     PAGES 
by-products,   363;  Slaughter-house  and  other  animal 
refuses,  364. 

CHAPTER  XV 

THE  PRODUCTION  OF  CATTLE  FOODS     .       .       .       .       .  272-280 

Adaptability  of  crops  to  environment,  365;  New  vs. 
old  species  of  plants,  366;  Adaptability  of  crops  to  kind 
of  animal  production,  367;  Productive  capacity  of 
crops,  368;  Crops  of  high  productivity,  369;  Home  sup- 
ply of  protein,  370;  Legumes  and  fertility,  371.  Soiling- 
crops:  Soiling-crops  a  necessity,  372;  Conditions  favora- 
ble to  soiling,  373;  The  economy  of  soiling-crops, 
374;  Selection  of  soiling-crops,  375;  Soiling-crop  area 
and  rotations,  376. 

CHAPTER  XVI 

THE  VALUATION  OF  FEEDING-STUFFS     .       ..  \    .       .       .281-291 

Basis  of  assigning  values  to  feeding-stuffs,  377;  Com- 
mercial values  of  feeding-stuffs,  378.  Valuation  of  feeds 
by  method  of  least  squares,  379;  Physiological  values, 
380;  Energy  values  as  a  basis  of  valuation,  381;  Con- 
ditions involved  in  the  selection  of  feeding-stuffs,  382; 
Digestibility  as  a  basis  for  selecting  feeding-stuffs, 
383;  Values  based  on  digestibility,  384;  Digestibility 
of  various  feeds,  385;  Valuations  based  on  protein  con- 
tent, 386;  Feed  values  based  on  feeding  experiments, 
387;  The  verdict  of  the  cow,  388. 

CHAPTER  XVII 
THE  SELECTION  AND  COMPOUNDING  OF  RATIONS        .       .  292-306 

Palatableness  as  a  factor  in  feeding  animals,  389; 
Adaptation  of  rations,  390;  Physiological  require- 
ments, 391;  Feeding  standards,  392;  Nutritive  ratio, 
393;  Calculating  a  ration,  394;  Calculation  of  digestible 
nutrients,  395;  Digestible  nutrients  in  a  given  ration, 
396;  Correcting  an  insufficient  ration,  397;  Relation 


XIV  CONTENTS 

of  ration  to  size  of  animal,  398;  The  protein  supply,  PAOES 
399;  Earlier  protein  standards  revised,  400;  Presence  of 
growth-promoting  bodies,  401;  Influence  of  ration  on 
quality  of  product,  402;  Home  supply  of  feeding-stuffs 
to  be  considered,  403;  Selection  of  a  ration  largely  a 
business  matter,  404. 

CHAPTER  XVIII 

MAINTENANCE  RATIONS 307-318 

Definition  of  maintenance  ration,  405;  Character  of 
maintenance  ration,  406;  Uses  of  production  ration,  407: 
•Maintenance  ration  easily  provided,  408.  Maintenance 
Ration  for  Bovines:  Various  investigations  concerning 
maintenance  needs,  409;  Fasting  katabolism  as  a 
measure  of  maintenance  needs,  410;  Distribution  of 
maintenance  energy,  411;  Use  of  nutrients  in  fasting 
metabolism,  412;  Computation  of  maintenance  needs, 
413;  Maintenance  rations  for  bovines,  414.  Maintenance 
Food  for  Horses:  Studies  of  the  maintenance  needs  of  the 
horse,  415;  Maintenance  rations  for  horses,  416;  Main- 
tenance food  for  sheep,  417. 

CHAPTER  XIX 

MILK  PRODUCTION 319-345 

Composition  of  cow's  milk,  418;  Milk  secretion, 
419;  Food  sources  of  milk  proteins,  420;  Food  sources  of 
milk-fats,  421;  The  rate  of  formation  of  milk  solids, 
422;  Uses  of  nutrients  in  milk  production,  423;  Pro- 
tein requirements  for  milk  production,  424;  Relative 
importance  of  protein  overstated,  425.  Feeding 
Standards  for  Dairy  Cows:  Thaer's  hay  values,  426; 
Grouven's  milk-feeding  standards,  427;  Wolff's  feeding 
standard,  428;  Kuhn's  feeding  standard,  429;  The 
Wolff-Lehmann  feeding  standards,  430;  American  feed- 
ing standards,  431;  Woll's  standard,  432;  Standards 
for  milk  production  based  on  elaborate  American  feed- 
ing experiments,  433;  Requirements  of  certain  feeding 
standards  for  dairy  cows,  434;  Calculation  of  rations 


CONTENTS  XV 

for  dairy  cows,  435;  Suggested  practical  rations  for  PA<3ES 
daily  cows,  436;  The  sources  of  commercial  protein  for 
milk  production;  the  home  supply,  437;  Commercial 
proteins,  438;  No  single  protein  food  essential,  439. 
The  Relation  of  Food  to  the  Composition  and  Quality 
of  Milk:  Effect  of  food  on  the  proportion  of  milk  solids, 
440;  Effect  of  food  on  the  constitution  of  milk  solids,  441 ; 
Influence  of  food  on  the  milk-fats,  442 ;  Effect  of  food  on 
the  flavors  of  milk  and  its  products,  443. 

CHAPTER  XX 

FEEDING  GROWING  ANIMALS    .     \.     <.       .       .       .       .346-361 

The  requirements  for  growth,  444;  Food  freely  appro- 
priated by  growing  animal,  445;  Influence  of  kind  of 
food  on  kind  of  growth,  446;  Estimated  energy  require- 
ments for  one  pound  of  gain  in  weight  by  growing 
cattle  and  sheep,  447;  Milk  for  young  animals,  448.  The 
Feeding  of  Calves:  Skimmed  milk  as  a  substitute  for 
whole  milk  in  feeding  calves,  449;  Calf  rations  without 
milk  products,  450.  The  Feeding  of  Lambs:  Feeding 
ewes  with  lamb,  451;  Grain  foods  accessible  to  lambs, 
452;  Standards  for  growing  sheep,  453.  Feeding  Colts: 
Food  as  related  to  quality  of  the  "horse,  454;  Feeding 
the  colt  through  the  dam,  455;  Rations  for  the  colt 
before  weaning,  456;  Oats  as  horse  feed,  457;  Rations 
for  growing  colts,  458. 

CHAPTER  XXI 
FEEDING  ANIMALS  FOR  THE  PRODUCTION  OF  MEAT  362-386 

Beef  Production:  Nature  of  the  growth  with  beef 
production,  459;  Rate  of  increase  of  fattening  animals, 
460;  The  food  needs  of  the  fattening  steer,  461 ;  Scientific 
experiments  with  fattening  animals,  462 ;  Practical 
feeding  experiments  in  fattening  animals,  463;  German 
fattening  for  bovine's  rations  excessive,  464;  The  selec- 
tion of  a  fattening-ration,  465;  Suggested  rations  for 
fattening  steers,  466.  Mutton  Production:  Place  of 
sheep  on  the  farm,  467;  The  nature  and  extent  of  the 


XVI  CONTENTS 

growth  in  fattening  sheep,  468;  Food  needs  of  fatten-  PAGES 
ing  sheep,  469;  Quantity  of  nutrients  for  fattening 
sheep,  470;  The  selection  of  a  ration  for  sheep,  471. 
Pork  Production:  Changes  in  pork  production,  472; 
Character  of  the  growth  in  pork  production,  473;  Food 
requirements  for  pork  production,  474;  Pigs  unwisely 
fed,  475;  Point  of  view  in  feeding  pigs,  476;  Influence  of 
ration  on  the  development  of  swine,  477;  Dairy  wastes 
as  food  for  pigs,  478;  Protein  foods  other  than  milk 
products  for  swine,  479;  Forage  crops  for  swine,  480. 

CHAPTER  XXII 

FEEDING  WORKING  ANIMALS         >.     ' 387-398 

The  horse  a  machine,  481 ;  The  work  performed  by  a 
horse,  482;  Influence  of  conditions  on  the  food  expendi- 
ture for  a  unit  of  work,  483;  The  food  requirements  of  a 
working  horse,  484;  Estimate  of  work  ration  for  the 
horse  based  on  energy  relations,  485;  Source  of  the  ration 
for  working  horses,  486;  Nutritive  ratio  for  working 
horses,  487;  Oats  for  working  horses,  488;  Suggested 
rations  for  working  horses,  489. 


CHAPTER  XXIII 

THE  FEEDING  OF  POULTRY.  By  William  P.  Wheeler  .        .  399-417 

Food  needs  of  birds  intensive,  490;  Kinds  of  foods  for 
poultry,  491;  Incidental  effects  of  the  food  with  laying 
hens,  492;  Digestive  apparatus  of  birds,  493;  Constitu- 
ents of  the  body  of  the  hen,  494;  Composition  of  eggs, 
495;  Necessity  for  considering  the  water-supply,  496; 
Efficiency  of  protein  from  animal  sources  for  fowl,  497; 
Ash  constituents  important  for  egg  production,  498; 
Common  salt  a  necessity  for  fowls,  499;  Supply  of  grit 
for  fowls,  500;  Feeding  standards  for  fowls,  501;  Main- 
tenance rations  for  fowls,  502;  Rations  for  laying  hens, 
.503;  Rations  for  young  birds,  504;  Adaptability  of  vari- 
ous foods  for  fowls,  505;  Knowledge  of  the  nutrition  of 
fowls  limited,  506. 


CONTENTS  Xvii 

CHAPTER  XXIV  pAQEg 

THE  RELATION  OF  FOOD  TO  PRODUCTION     ....  418-424 

Food  unit  defined,  507;  The  unit  of  production,  508; 
Factors  involved  in  food  economics,  509;  Relation  of 
food  to  production  with  various  species,  510. 

CHAPTER  XXV 

GENERAL  MANAGEMENT 425-434 

Factors  in  general  management  of  animals,  511;  The 
selection  of  cows,  512;  The  general-purpose  cow,  513; 
The  selection  of  animals  for  meat  production,  514; 
Relation  of  age  to  meat  production,  515;  Manipulation 
of  the  ration,  516;  Quantity  of  the  ration,  517;  Environ- 
ment and  treatment  of  animals,  518;  Cruelty  to  ani- 
mals, 519. 

APPENDIX 435-463 

1.  Average  composition  of  American  feeding-stuffs         .  435 

2.  Average  coefficients  of  digestion 441 

3.  Computation  of  energy-production  values  .        .  448 

4.  Food  standards  for  milk  production  as  developed  by 

Haecker,  Savage,  and  Eckles 455 

5.  Feeding  standards 457 

6.  Fertilizing  Constituents  of  American  Feeding-Stuffs.         460 


PART  I 
THE  PRINCIPLES  OF  FEEDING 


THE  FEEDING  OF  ANIMALS 


CHAPTER  I 

INTRODUCTION:    MAN'S  RELATION  TO 
ANIMAL  LIFE 

THERE  was  a  time  somewhere  in  the  dim  past  when 
the  beast  of  the  field  knew  no  master.  The  only  obe- 
dience which  he  rendered  to  a  superior  power  was  an 
unconscious  submission  to  Nature's  stern  forces.  He 
wandered  forth  at  will  to  find  in  the  untilled  pastures 
such  food  as  the  wild  herbage  afforded,  and,  unre- 
strained, he  sought  a  place  of  rest  in  the  tangled  thicket. 
He  knew  no  refuge  from  the  winter's  cold  and  storm 
but  some  sheltered  nook  or  forest  recess  to  which  his 
brute  intelligence  guided  him,  and  he  was  his  own  defense 
against  the  dangers  which  beset  him. 

Man  had  not  come  to  be  a  controlling  factor  in  the 
development  of  the  various  forms  of  animal  life.  If  the 
brute  knew  him  at  all,  it  was  as  the  huntsman,  as  an 
enemy,  but  not  as  a  superior  to  whom  must  be  paid  a 
tribute  of  service  or  of  food  and  clothing.  The  wild 
ox  and  horse  possessed  those  characteristics  which  best 
fitted  them  to  cope  with*  the  untoward  conditions  of 
their  environment;  but  there  had  not  yet  appeared  those 
specialized  capacities  of  growth,  draft,  speed,  or  pro- 
duction which  now  render  these  animals  so  very  valuable 
for  the  service  and  sustenance  of  the  human  family. 

The  qualities  developed  were  those  demanded  by  the 
(3) 


4  THE  FEEDING  OF  ANIMALS 

necessities  of  existence  without  reference  to  utility  as 
measured  by  the  needs  of  a  higher  form  of  life.  The  fiber 
of  the  body  must  possess  endurance,  and  it  mattered 
little  whether  or  not  the  muscle  could  furnish  a  juicy 
steak.  The  brute  mother  must  defend  her  young  and 
supply  it  with  milk,  and  this  being  accomplished,  her 
maternal  functions  ceased.  She  was  neither  so  endowed 
that  she  could  open  the  fountains  of  her  life  to  feed  gen- 
erously a  not  too  grateful  master,  nor  so  submissive 
that  she  would.  The  wild  horse  must  be  fleet  and  endur- 
ing that  he  might  escape  the  enemy,  but  not  that  he 
might  bear  heavy  burdens  or  win  a  contest  in  the  pre- 
scribed form  of  the  race-track. 

In  the  lapse  of  centuries  there  have  been  many  changes 
in  the  relation  of  man  to  the  animal  creation.  Bird 
and  beast  in  various  forms  have  come  to  minister  to 
man's  wants,  and  in  their  present  domesticated  condi- 
tion are,  in  their  turn,  utterly  dependent  upon  him  for 
the  food  and  shelter  which  are  necessary  to  their  physical 
welfare,  or  even  existence.  It  is  not  too  much  to  assert 
that  the  domestic  animal,  in  the  artificial  environment 
imposed  upon  it,  is  entirely  at  man's  mercy,  even  in 
the  development  of  those  attributes  and  chaTacteris- 
tics  which  otherwise  would  be  determined  by  the  demands 
of  an  unaided  warfare  with  nature.  The  juicy  sirloin  of 
the  shorthorn,  the  almost  abnormal  milk  glands  of  the 
champion  butter  cow,  the  delicate  fiber  of  merino  wool, 
and  the  marvelous  speed  of  the  modern  race-horse  are 
evidences  of  man's  skill  in  recasting  natural  types  into 
forms  of  greater  usefulness  to  him.  From  the  animal 
of  nature,  under  the  direction  of  a  higher  intelligence, 
has  proceeded  the  animal  of  civilization,  an  organism 
obedient  to  the  environment  which  has  been  created  for  it. 


INTRODUCTION  5 

This  interdependence  of  man  and  the  lower  orders 
of  life  has  a  vast  economic  significance.  A  large  part 
of  human  activity  is  devoted  to  the  production  and 
transportation  of  food  for  animals  and  to  the  traffic  in 
the  products  of  the  dairy,  slaughter-house,  and  sheep- 
fold,  and  to  their  utilization  in  various  ways.  The  pros- 
perity of  every  farm  is  maintained  to  a  greater  or  less 
extent  by  feeding  domestic  animals,  and  our  railroads, 
our  markets,  in  fact,  nearly  all  our  important  business 
enterprises,  are  more  or  less  dependent  upon  the  extent 
and  prosperity  of  animal  husbandry. 

THE    CONDITIONS   AND    PROBLEMS   INVOLVED   IN 
FEEDING  ANIMALS 

The  first  and  simplest  form  of  animal  husbandry  is 
that  which  was  practised  by  the  nomad.  His  flocks 
and  herds  subsisted  wholly  by  grazing  and  were  moved 
from  place  to  place  according  to  the  supply  of  forage 
afforded  by  different  localities.  No  shelter  was  pro- 
vided for  the  animals  and  no  food  was  stored  for  their 
use.  The  only  intelligence  or  special  knowledge  that 
was  brought  to  bear  upon  the  business  of  the  herdsman 
was  a  familiarity  with  the  traditions  and  superstitions 
touching  the  care  of  cattle  and  the  acquaintance  which 
a  roving  life  would  give  with  the  pastures  furnishing 
the  most  abundant  and  sweetest  wild  grasses  during  the 
various  seasons  of  the  year.  There  was  not  then  even 
a  dim  promise  of  the  modern  traffic  in  meats  or  of  the 
fine  art  of  dairying  as  we  now  know  it.  As  man  began  to 
give  up  this  wandering  life,  erect  permanent  dwellings, 
and  confine  his  ownership  of  land  to  definite  limits,  he 
acquired  the  art  of  tillage,  not  only  that  he  might  have 


6  THE   FEEDING  OF   ANIMALS 

food  for  his  family  but  also  for  his  cattle.  He  then  began 
to  store  fodder  in  stacks,  and  later  in  barns,  to  meet  the 
demands  of  the  inclement  portions  of  the  year. 

For  centuries,  however,  grazing  was  the  chief  depen- 
dence for  securing  the  production  of  meat  and  milk  because 
the  foods  supplied  during  the  cold  season  were  not  in 
such  abundance  or  so  nutritious  as  to  sustain  continu- 
ous growth  or  milk  secretion.  Even  within  the  remem- 
brance of  men  now  living,  live-stock  was  not  expected 
to  produce  an  increase  during  the  winter  months  but  was 
simply  maintained  from  autumn  until  spring  in  order 
that  profits  might  be  realized  from  summer  pasturage. 
Formerly  the  demands  of  the  market  were  much  simpler 
than  they  are  now.  Butter  and  cheese  were  produced 
almost  wholly  from  summer  dairying,  and  no  such  variety 
of  fresh  meats  was  offered  to  consumers  during  the  entire 
year  as  is  now  the  case.  But  great  changes  have  occurred 
during  the  last  fifty  years,  more  especially  during  the  past 
twenty-five.  First  of  all,  we  have  a  modern  type  of  animal, 
greatly  unlike  that  of  previous  times.  The  ideal  dairy 
cow  of  today  is  a  high-pressure  milk-machine  extremely 
sensitive  to  her  environment  and  demanding  a  degree  of 
care  in  management  and  feeding,  if  she  is  to  do  her  safe 
maximum  work,  which  was  not  necessary  with  coarser 
and  less  delicate  organisms.  Every  successful  dairyman 
must  now  provide  proper  v  winter  quarters  for  his  herd 
and  throughout  the  entire  year  must  supply  rations 
that  will  support  continuous,  generous  production.  He 
must  do  this,  too,  by  the  use  of  a  greater  variety  of 
foods  than  was  formerly  available.  Not  only  has  the 
number  of  useful  forage  crops  greatly  increased,  but  the 
average  farmer  no  longer  produces  all  the  food  which  his 
animals  consume.  He  now  buys  numerous  kinds  of  com- 


INTRODUCTION  7 

mercial  feeding-stuffs.  These  purchased  materials  are 
not  wholly  the  cereal  grains  whose  value  through  long 
experience  has  come  to  be  measured  by  certain  prac- 
tical standards,  but  they  consist  in  part  of  compara- 
tively new  by-products  from  the  manufacture  of  oils, 
starch,  and  human  food  preparations — feeding-stuffs 
which  differ  greatly  in  their  nutritive  properties.  Besides 
all  these  changes,  animal  husbandry  is  now  called  upon 
as  never  before  to  feed  the  prosperous  part  of  humanity 
with  high-class  products  having  special  qualities  of 
texture  and  flavor  that  depend  to  some  extent  upon 
feeding.  Certainly  the  conditions  and  problems  to  be 
met  in  this  branch  of  human  industry  have  grown  more 
and  more  complex. 

We  must  add  to  this  the  fact  that,  as  is  true  with 
every  department  of  man's  activity,  science  has  laid 
her  hands  upon  the  business  of  the  farmer  and  has  forced 
him  into  a  new  range  of  thought  and  practice.  This 
influx  of  knowledge  has  greatly  influenced  the  require- 
ments for  meeting  a  sharpened  competition  and  has 
rendered  it  imperative  for  the  practitioner  to  bring  to 
bear  upon  a  great  variety  of  agricultural  problems  a 
clear  understanding  of  fundamental  facts  and  principles. 

The  feeding  of  animals  involves  many  difficult  ques- 
tions. These  begin  with  the  production  of  forage  and 
grain  crops  where  it  is  necessary  to  discover  what  ones 
will  yield  the  largest  food-values  to  a  unit  of  expendi- 
ture. Economy  demands  that  the  several  feeding-stuffs 
which  are  at  command  shall  be  so  combined  that  there 
shall  be  no  waste  of  material  or  energy.  With  several 
considerations  in  view,  a  decision  must  be  reached  as  to 
the  most  profitable  commercial  foods  to  purchase  when 
the  number  is  large  and  the  range  of  prices  is  wide.  The 


8  THE  FEEDING  OF  ANIMALS 

influence  of  the  various  foods  upon  the  quality  of  the 
product,  especially  dairy  products,  has  in  recent  years 
become  an  important  matter.  These  and  related  problems 
confront  the  stockman  and  dairyman,  and  they  demand 
for  their  wise  solution  more  than  what  is  ordinarily 
designated  as  practical  experience.  The  investigator 
who  shall  successfully  inquire  into  these  matters  must 
possess  scientific  qualifications  of  a  high  order;  and  the 
practical  man,  who,  in  a  business  way,  conforms  his 
methods  to  the  highest  standard  which  scientific  research 
has  already  made  possible  must  be  familiar  with  the 
knowledge  fundamental  to  the  feeder's  art. 


CHAPTER  II 
THE  RELATIONS  OF  PLANT  AND  ANIMAL  LIFE 

ANIMAL  nutrition  has  an  intimate  relation  to  plant 
growth.  The  farmer  producing  meat  and  milk  should 
understand  the  relation  which  animal  life  sustains  to 
plant  life  in  order  that  he  may  so  direct  plant  production 
as  to  best  serve  his  purposes  in  feeding  whatever  class  of 
animals  he  utilizes.  The  efficiency  of  the  various  plant 
products  in  sustaining  animal  life  is  to  him  a  matter  of 
great  importance. 

1.  Origin  of  animal  foods. — The  compounds  which 
together  constitute  animal  foods  have  their  origin  in  plant 
life.  For  this  reason,  a  study  of  the  fundamental  facts 
of  animal  nutrition  begins  with  the  plant.  It  is  in  the 
plant  that  the  simple  compounds  derived  from  the  soil 
and  air  are  utilized  for  the  production  of  the  more  highly 
complex  compounds  which  are  used  for  the  growth  of 
the  animal  body  and  for  the  maintenance  of  its 
activities. 

As  soon  as  the  young  rootlets  from  a  germinating  seed 
come  in  contact  with  the  soil  and  the  first  leaves  reach  the 
air,  assimilative  growth  begins  and  continues,  as  for 
instance,  in  the  wheat  plant  until  the  stalk  of  grain  has 
reached  its  full  height  and  has  attained  the  ultimate 
object  of  its  existence  in  the  production  of  seed.  Certain 
agricultural  plants  have  the  capacity  of  producing  not 
less  than  10,000  pounds  an  acre  in  a  single  year  of  plant 
substance  which  may  serve  as  food  for  animals. 

(9) 


10  THE   FEEDING  OF  ANIMALS 

2.  The  plant  stores  energy. — Plant  life  both  synthesizes 
simpler  compounds  into  complex  organic  substance  and 
stores  energy.    We  get  evidence  of  this  fact  when  wood 
is  utilized  as  fuel  for  the  production  of  heat,  heat  being 
one  form  of  energy.    Scientific  investigation  has  traced 
the  source  of  this  heat  to  the  chemical  energy  of  the  sun's 
rays,  which  becomes  stored  in  the  plant.    Combustion 
of  the  plant  tissue  liberates  this  energy  in  another  form. 
Not  only  does  this  energy  become  available  as  heat,  but 
it  is  also  available  for  a  variety  of  uses  in  the  animal 
body.   (See  Pars.  206,  207.) 

3.  Plant  substance  a  source  of  animal  substance. — 
The  animal  body,  outside  of  the  water  which  it  con- 
tains, has  its  immediate  origin  in  the  food  which  the 
animal  consumes.    The  mass  of  bone  and  flesh  which 
make  up  the  body  of  the  immense  bullock  is  derived  from 
the  plant  substance  which,  in  other  combinations,  was 
collected  from  the  soil  and   air.    The  animal  eats  his 
daily  ration  and  makes  his  daily  gain  of  tissue.    If  food 
is  withdrawn,  his  body  wastes  and  dies.   If  his  food  varies 
in  amount,  his  growth  is  somewhat  proportional  to  the 
quantity  eaten.    It  is  self-evident  that  the  bones,  blood, 
and  flesh  of  an  animal  are  derived  from  what  he  eats. 

4.  The  plant  a  source  of  animal  heat. — The  plant  not 
only  supplies  building-material  for  the  animal  body,  but 
is  the  source  of  the  heat  with  which  the  animal  organ- 
ism is  kept  warm.    No  matter  how  cold  the  surrounding 
atmosphere,  we  find  that  when  in  health  the  temperature 
of  the  ox  remains  at  about  101°  F.,  with  but  small  varia- 
tion.   Just  as  we  warm  a  room  through  the  combustion 
of  vegetable  matter,  such  as  wood,  so  the  temperature 
of  the  animal  is  kept  at  the  necessary  heat  by  the  com- 
bustion of  his  food.    The  combustion,  in  the  latter  case, 


PLANT  AND   ANIMAL  LIFE  11 

is  not  so  rapid  as  in  the  former,  but  the  changes  are  the 
same  though  more  slowly  carried  on. 

5.  Food  a  source  of  motive  power. — Food  not  only 
furnishes  the  constructive  material  for  the  ox's  body  and 
maintains  animal  heat,  but  it  also  supplies  the  animal 
machine  with  motive  power.  The  energy  which  the 
plant  acquires  during  its  time  of  growth,  through  the 
vital  processes  of  the  animal,  is  transformed  in  part 
into  motion.  An  animal  is  a  living  mechanism,  a  combina- 
tion of  muscles  and  levers  which  are  moved  not  by  means 
of  a  spontaneous  internal  generation  of  energy,  but 
through  a  supply  of  energy  from  without,  the  energy 
stored  by  the  plant.  (See  Pars.  236-241.) 


CHAPTER  III 

THE  CHEMICAL  ELEMENTS  INVOLVED  IN 
ANIMAL  NUTRITION 

IT  is  fundamentally  necessary,  to  an  intelligent  under- 
standing of  the  principles  and  economy  of  cattle-feeding, 
to  know  the  kinds  and  sources  of  the  materials  out  of 
which  vegetable  and  animal  tissues  are  constructed.  We 
are  primarily  concerned  with  chemical  elements. 

6.  Chemical  elements  involved  in  animal  growth. — 
Approximately  eighty  substances  are  now  believed  to  be 
chemical  elements,  i.  e.,  substances  that  have  not  been 
resolved  into  two  or  more  simpler  ones,  and  of  which,  so 
far  as  is  now  known,  all  forms  of  matter  are  composed. 
About  one-fifth  of  these  fundamental  substances  are 
involved  in  plant  growth,  those  that  occupy  a  prominent 
place  in  animal  nutrition  being  even  less  in  number. 
These  fifteen  elements  are  the  following,  some  of  which 
are  of  minor  importance:  carbon,  oxygen,  hydrogen, 
nitrogen,  sulfur,  phosphorus,  chlorine,  iodine,  silicon, 
fluorine,  potassium,  sodium,  calcium,  magnesium,  iron, 
and  manganese. 

At  ordinary  temperatures,  four  of  these,  oxygen, 
hydrogen,  nitrogen,  and  chlorine  are  gases  and  the  remain- 
ing ones  are  solids.  Carbon,  oxygen,  hydrogen,  and 
nitrogen  are  constant  and  important  ingredients  of  the 
atmosphere  and  they  exist  in  the  soil  in  gases  as  well  as 
in  the  various  combinations.  The  other  eleven,  though 
sometimes  present  in  the  air  in  minute  quantities,  are 

(12) 


THE   CHEMICAL   ELEMENTS  13 

found  to  no  appreciable  extent  outside  of  plants  and 
animals  except  as  fixed  compounds  in  water  and  in  the 
crust  of  the  earth.  These  fifteen  elementary  substances 
are  nearly  all  absolutely  essential  to  the  existence  of 
animal  life  as  now  constituted.  From  the  standpoint  of 
necessity,  they  are,  therefore,  nearly  all  of  equal  value; 
but,  if  we  take  into  consideration  the  relative  ease  and 
abundance  of  the  supply,  certain  ones  are  greatly  more 
important  than  the  others. 

THE   ELEMENTS   AND   THEIR   SOURCES 

7.  Carbon. — This  is  a  familiar  substance  in  common 
life.    Coal  and  charcoal  consist  chiefly  of  carbon,  while 
graphite,  much  used  in  lead-pencils  and  diamonds,  is 
pure  carbon.    Carbon  makes  up  a  large  proportion  of 
vegetable  and  animal  tissue.   This  is  made  evident  when 
vegetable  and  animal  tissues  become  black  through  heat- 
ing to  a  temperature  which  causes  them  to  decompose, 
leaving  the  carbon  as  a  residue  while  the  elements  with 
which  it  was  associated  are  driven  out.  The  dark  humus 
bodies  of  the  soil  have  undergone  somewhat  the  same 
change. 

8.  Carbon  in  the  air. — An  immense  quantity  of  carbon 
exists  in  the  air,  combined  with  oxygen  as  carbon  dioxid. 
The  average  proportion  of  this  compound  in  the  atmos- 
phere by  weight  is  approximately  .06  per  cent.    As  the 
weight  of  a  column  of  air  over  1  inch  square  of  the  earth's 
surface  is  fifteen  pounds,  it  follows  that  over  every  acre 
of  land  there  is  an  average  of  28.2  tons  of  carbon  dioxid, 
or  7.7  tons  of  carbon.  As  we  know  that  plants  draw  their 
supply  of  carbon  from  the  atmosphere  and  as  vegetable 
tissue  is  the  primary  source  of  this  element  to  the  animal, 


14  THE  FEEDING  OF  ANIMALS 

we  safely  reach  the  conclusion  that  the  carbon  in  the 
tissues  of  animal  life  was  once  floating  in  space. 

Boussingault  determined  the  average  yearly  amount  of 
carbon  withdrawn  from  the  air  by  the  crops  grown  on  a 
particular  field  during  a  period  of  five  years  to  be  4,615 
pounds.  A  large  crop  of  maize  or  alfalfa  would  acquire 
even  more  than  this.  Such  large  drafts  upon  the  atmos- 
pheric supply  of  carbon  raise  the  question  whether  this 
supply  remains  constant.  Investigation  has  shown  that 
it  does.  The  processes  of  decay  through  oxidation  of 
vegetable  and  animal  substance  on  the  earth's  surface, 
the  combustion  of  wood  and  coal  as  fuel  and  of  food  com- 
pounds by  animal  life  are  all  returning  carbon  to  the  air 
as  carbon  dioxid  and  it  would  appear  that  a  balance  is 
being  maintained.  The  round  traveled  in  the  circula- 
tion of  carbon  is  from  the  air  to  the  plant,  from  the  plant 
to  the  animal,  and  from  the  animal  back  to  the  air — a 
cycle  of  movement  that  has  always  existed  and  which  will 
continue  so  long  as  life  exists. 

9.  Oxygen. — This  element,  next  to  carbon,  is  the  most 
abundant  component  of  the  vegetable  and  animal  tissues. 
It  is  second  to  none  in  the  importance  of  its  relations  to  the 
vital  processes  of  nearly  all  forms  of  life.  We  are  not 
familiar  with  this  substance  by  sight  because  it  is  a  trans- 
parent, colorless  gas.  The  air  is  over  one-fifth  oxygen  by 
volume.  More  than  21,000,000  pounds  of  this  element  are 
contained  in  the  air  above  a  single  acre  of  land,  a  quan- 
tity which  remains  remarkably  constant  and  is  practically 
uniform  over  the  entire  surface  of  the  globe.  Like  carbon, 
it  is  being  continuously  withdrawn  from  the  air  for  pur- 
poses of  combustion  and  is,  like  carbon,  as  continuously 
returned.  Water  contains  nearly  89  per  cent  of  oxygen, 
and  it  is  estimated  that  the  crust  of  the  earth  is  one-half 


THE   CHEMICAL  ELEMENTS  15 

oxygen.  That  which  enters  directly  into  the  uses  of  animal 
life  is  derived  chiefly  from  the  atmosphere  and  water. 

10.  Uses  of  oxygen. — All  life,  whether  vegetable  or 
animal,  is  dependent  on  the  use  of  oxygen,  during  which 
use  this  element  passes  into  fixed  combinations  and  back 
again  into  the  free  form.    The  free  oxygen  of  the  air  is 
used  by  an  animal  in  breathing  and  this  it  returns  to  the 
air  in  part  combined  with  carbon  as  carbon  dioxid.    On 
the  other  hand,  the  plant  appropriates  the  carbon  dioxid 
and,  through  synthetical  processes,  the  carbon  is  built 
into  the  plant  tissues  and  the  oxygen,  which  is  set  free,  is 
returned  to  the  atmosphere  and  may  be  used  to  sustain 
the  demands  of  animal  life.    Oxygen  is  a  factor  in  all 
processes  of  decay  and  in  many  other  chemical  changes. 
Fire  is  due  to  its  union  with  the  elements  of  the  fuel.   It 
is  the  agent  which  maintains  combustion  in  the  furnaces 
of  our  industries.    The  energy  derived  from  the  sun's 
rays,  which  is  stored  in  vegetable  tissue,  when  the  oxygen 
is  torn  from  its  union  with  carbon  is  set  free  when  through 
combustion  the  oxygen  is  returned  to  its  former  combina- 
tion.  This  circulation  of  oxygen  is  effected  through  the 
opportunities  offered  by  the  vital  processes  of  the  plant 
and  animal.    (See  Par.  207.) 

11.  Hydrogen. — In  a  free  state,  this  element  is  the 
lightest  known  gas  and  is  found  abundantly  in  nature 
only  in   combination  with    other   elements.     A  minute 
proportion  exists  in  the  air  which  is  derived  from  volcanic 
action  and  possibly  from  decay  under  certain  conditions. 
When  hydrogen  and  oxygen  are  combined  in  the  forma- 
tion of  water,  intense  heat  is  produced.    Hydrogen  con- 
stitutes about  one-ninth  of  water  by  weight  and  it  is 
found  also  in  a  large  number  of  soil  compounds.   It  is  an 
essential  constituent  of  vegetable  and  animal  tissues,  but 


16  THE  FEEDING  OF  ANIMALS 

exists  in  these  in  a  much  smaller  proportion  than  carbon 
or  oxygen.  Its  source  to  the  plant  is  largely  water  and  it 
is  furnished  to  the  animal  in  water  and  other  compounds. 

12.  Nitrogen    and    its    compounds    have    been    the 
subject   of    much    scientific    investigation    in   their   re- 
lations to  agricultural  practice.    Like  oxygen,  nitrogen 
is    an    invisible,    tasteless,    and    odorless    gas,    which, 
according  to  previous  determinations,  forms  about  77 
per  cent  of  atmospheric  air  by  weight.   The  existence  in 
the  air  of  newly  discovered  elements,  such  as  argon,  has 
modified  previous  determinations.     The  only  place   in 
nature  where  nitrogen  or  its  compounds  exist  in  large 
quantities,  outside  of  the  air  and  in  the  tissues  of  living 
organisms,  is  the  sodium  nitrate  beds  which  are  found 
in  Chile  and  other  localities.   Soil  spaces  contain  nitrogen 
and  it  is  taken  into  solution  in  small  proportions  in  all 
natural  waters.    It  is  found  in  mineral  and  organic  com- 
pounds in  the  soil,  but  in  quantities  very  insignificant  as 
compared  with  such  elements  as  oxygen  and  silicon.  Few 
agricultural  soils  contain  over  }^  per  cent  of  combined 
nitrogen.    Minute  quantities  of  its  compounds,  such  as 
ammonium  carbonate  and  ammonium  nitrate,  exist  in 
the  atmosphere,  which  are  being  constantly  carried  to  the 
soil  in  rain-water  and  as  constantly  replaced  by  ammonia 
from  decomposing  animal  and  vegetable  matter  and  by 
the  products  of  oxidation  of  nitrogen  through  combustion 
and  electrical  action.    Although  the  compounds  of  nitro- 
gen exist  in  a  comparatively  small  proportion,  they  play 
a  very  prominent  part  in  agriculture,  both  commercially 
and  physiologically.   The  nitrogen  balance  of  the  farm  is 
important  both  to  the  crop-producer  and  the  cattle-feeder. 

13.  Supply    of    nitrogen. — The    available    supply    of 
nitrogen  compounds  is  often  dangerously  near  the  demand, 


THE   CHEMICAL   ELEMENTS  17 

and  sometimes  below  it.  The  large  quantity  found  in  the 
air  is  inert  for  animal  uses,  and  is  ignored  by  a  large 
majority  of  plants.  Much  of  that  in  the  soil  is  also  un- 
available. Its  immediately  useful  compounds  on  the  farm 
are  constantly  subject  to  loss  through  fermentations  which 
the  farmer  can  not  wholly  prevent  and  through  soil  losses 
which  are  to  some  extent  beyond  control.  The  sale  of 
crops  removes  from  the  farm  much  nitrogen.  The  sources 
of  supply  to  balance  this  outgo  are  the  nitric  acid  and 
ammonia  of  the  rainfall,  the  free  nitrogen  captured  by  a 
class  of  plants  known  as  legumes,  that  which  is  secured 
through  purchase  of  fertilizers  and  the  residues  of  animal 
foods.  These  facts  relate  primarily  to  plant  production, 
but  they  also  sustain  an  essential  relation  to  the  main- 
tenance of  animal  life. 

14.  Uses  of  nitrogen. — Physiologically,  the  nitrogen 
compounds  of  foods  stand  in  the  front  rank.   These  com- 
pounds are  necessary  building-material  for  the  funda- 
mental tissues  of  the  animal,  and  are  intimately  related  to 
prominent  chemical  changes  which  are  involved  in  growth 
and  in  the  maintenance  of  life. 

Nitrogen  compounds  have  come  to  have  an  important 
place  in  commerce.  It  is  the  most  costly  ingredient  of 
fertilizers  and  the  value  of  commercial  cattle  foods  is  in 
part  dependent  upon  their  content  of  these  compounds. 
For  all  these  reasons,  the  partial  control  which  the  farmer 
might  now  assume  over  the  income  and  outgo  of  nitrogen 
compounds  has  become  an  important  feature  of  farm 
economics.  (See  Par.  59.) 

15.  Argon. — Argon  exists   in  the  atmosphere  to  the 
extent  of  about  nine-tenths  of  1  per  cent.  So  far  as  known, 
argon  does  not  function  in  vegetable  and  animal  life. 

16.  Sulfur. — This  common  and  familiar  substance  is 


18  THE  FEEDING  OF  ANIMALS 

found  in  all  soils  and  natural  waters  and  in  all  the  higher 
forms  of  animal  and  vegetable  life.  We  know  it  as  "brim- 
stone" when  fused  in  sticks  and  as  "flowers  of  sulfur" 
when  in  a  finely  divided  form.  Its  most  common  com- 
mercial compounds  are  sulfuric  acid  and  the  sulfates  of 
potassium,  sodium,  calcium,  and  magnesium.  Sulfur  is  an 
element  essential  to  the  building  up  of  some  of  the  most 
important  tissues  of  the  animal  body  and  is  supplied  in 
food  in  the  form  of  the  sulfates  and  in  protein  com- 
binations. (See  Par.  64.) 

17.  Phosphorus. — This  element  occupies  a  very  impor- 
tant place  in  animal  nutrition.  It  does  not  exist  in  nature 
in  an  uncombined  form  and  that  found  in  laboratories  is 
produced  only  by  chemical  means,  but  its  compounds  are 
widely  distributed,  those  in  the  soil  being  chiefly  the 
phosphates  of  calcium,  magnesium,   and    iron.     Large 
deposits  of  calcium  phosphate  are  known,  from  which  is 
obtained  the  crude  phosphatic  rock  that  serves  as  a  basis 
for  the  manufacture  of  commercial  fertilizers.  All  feeding- 
stuffs  in  their  natural  forms  contain  phosphorus  com- 
pounds, such  as  phosphates,  certain  fats,  and  organic 
nitrogen  compounds.    Phosphorus  is  a  constituent  of  the 
flesh  of  animals,  and,  combined  with  lime,  constitutes  a 
large  part  of  bone.  (See  Par.  55.) 

18.  Chlorine. — The  chief  source  of  chlorine  to  animal 
life  is  common  salt.    In  some  form  or  combination  it  is 
essential  to  the  nutrition  of  the  animal.    In  a  free  state, 
at  ordinary  temperatures,  it  is  a  greenish  colored,  dis- 
agreeable gas.    When  combined  with  hydrogen,  it  forms 
hydrochloric  acid — a  compound  that  occupies  a  promi- 
nent place  in  the  digestion  of  food.   Any  ordinary  mixed 
ration  contains  this  element  in  a  quantity  sufficient  for 
the  animal's  needs.    (See  Par.  144.) 


THE   CHEMICAL  ELEMENTS  19 

19.  Iodine. — Iodine  is  distributed  in  nature  only  in 
minute  quantities.   It  is  apparently  absent  in  some  plants, 
but  is  found  in  minute  quantities  in  others.   Nevertheless 
it  appears  to  exercise  important  functions  in  animal  life. 

20.  Potassium. — Familiar  compounds  of  this  element 
are  the  potassium  carbonate  leached  from  wood-ashes, 
saleratus,  and  the  caustic  potash  of  the  market.    This 
element  is  found  in  the  flesh  of  all  animals,  mostly  as  the 
phosphate,  and  is  abundantly  supplied  for  the  purposes 
of  nutrition   in  the  ordinary   combinations  of  natural 
feeding-stuffs. 

21.  Sodium. — This  is  the  basal  element  of  common 
salt,  a  compound  which  is  furnished  to  domestic  animals 
in  a  liberal  supply.    This  is  the  only  sodium  compound 
which  it  is  necessary  to  consider.  Sodium  plays  an  impor- 
tant part  in  the  digestion  of  food  as  it  is  the  basis  of  cer- 
tain bile  salts  and  is  concerned  in  other  ways  in  the 
digestive  processes.    (See  Par.  151.) 

22.  Calcium. — The  most  commonly  known  compound 
of  this  element  is  lime,  which  is  calcium  united  with 
oxygen.  Large  masses  of  lime-rock,  or  calcium  carbonate, 
exist  in  many  parts  of  the  earth's  surface.   All  soils  con- 
tain lime  compounds.    Its  universal  presence  in  plant 
tissues  and  in  the  milk  of  all  animals  in  most  instances 
assures  a  sufficient  supply  to  meet  the  demands  of  animal 
life.    The  growing  animal  makes  a  generous  use  of  lime 
because,  in  union  with  the  phosphoric  acid,  it  is  the  chief 
building-material  of  the  bony  framework.    A  deficiency 
of  food  lime  causes  an  abnormal  development  of  the  bony 
structure.    Lime  is  especially  important  for  poultry,  for 
egg-shells  are  mostly  a  lime  compound.    (See  Par.  55.) 

23.  Iron. — The  common  properties  of  iron  are  familiar 
to  everyone.    Iron  rust  and  iron  ore  are  oxides  of  this 


20 


THE  FEEDING  OF  ANIMALS 


element.  Iron  is  taken  up  by  plants  and  animals  in  small 
quantities  only,  but  is  absolutely  essential  to  their  growth 
and  welfare  because  of  its  important  relation  to  certain 
metabolic  processes.  (See  Par.  200.) 


PROPORTIONS   OF   THE   ELEMENTS   IN    PLANTS   AND 
ANIMALS 

In  order  to  reach  an  intelligent  understanding  of  the 
relation  of  supply  and  demand  which  exists  between  the 
vegetable  and  animal  kingdoms  and  the  raw  materials 
of  the  inorganic  world,  it  is  necessary  to  know  the  propor- 
tions in  which  the  elements  are  found  in  living  organisms. 

24.  Elements  in  plants. — It  has  been  estimated  by  a 
German  scientist,  Knop,  that  if  all  the  species  of  the 
vegetable  kingdom,  exclusive  of  the  fungi,  were  fused  into 
one  mass,  the  ultimate  composition  of  the  dry  matter  of 
this  mixture  would  be  the  following: 


Carbon 

Oxygen •  \  ~. 

Hydrogen    .    .    .    .    .    .  * 

Nitrogen >-;., 

Mineral  compounds  (ash) 


Per  cent 

45 

42 
6.5 
1.5 
5 


The  composition  of  various  single  species  or  parts  of 
a  plant,  such  as  the  fruit  or  straw,  shows  considerable 
variation  from  these  average  figures: 

TABLE  I 


Carbon 

Oxygen 

Hydrogen 

Nitrogen 

Ash 

Per  cent 

Per  cent 

Per  cent 

Per  cent 

Per  cent 

Clover  hay     

47.4 

37.8 

5. 

2.1 

7.7 

Wheat  kernel     .... 

46.1 

43.4 

5.8 

2.3 

2.4 

Wheat  straw      .... 

48.4 

38.9 

5.3 

.4 

7.0 

Fodder  beets      .... 

42.8 

43.4 

5.8 

1.7 

6.3 

Fodder-beet  leaves    .    . 

38.1 

30.8 

5.1 

4.5 

21.5 

THE   CHEMICAL  ELEMENTS 


21 


Carbon  constitutes  a  larger  proportion  than  any  other 
element  of  the  dry  substance  of  plants  of  all  species. 
Oxygen  stands  next  in  order,  followed  by  hydrogen  and 
then  nitrogen.  It  is  an  important  fact  in  the  economy  of 
nature  that  those  elements  which,  on  the  average,  make 
up  93.5  per  cent  of  the  dry  matter  of  plants  have  as  their 
main  source  either  the  atmosphere  or  water.  Only  a 
small  percentage  of  the  dry  matter  is  drawn  from  the 
soil,  and  it  is  this  small  part  that  sustains  the  most  impor- 
tant economic  relations  to  the  farmer's  business. 

25.  Elements  in  plant  ash. — The  elements  of  the  ash 
vary  materially  in  relative  quantity  in  different  plants. 
The  following  table  gives  the  proportion  of  the  ash  ele- 
ments in  a  number  of  agricultural  products: 

TABLE  II 
ASH  ELEMENTS  IN  CEREAL  GRAINS  AND  VEGETABLES* 


1 

\ 

I 

1 

I 

I 

Carrots 

1 

1 
I 

(5 

Potassium  .... 

Per 
cent 
.51 

Per 

cent 
.36 

Per 
cent 
.46 

Per 
cent 
1.25 

Per 
cent 
1.89 

Per 

cent 
1.68 

Per 
cent 
1.93 

Per 
cent 
2.27 

Per 
cent 
2.18 

Sodium  ..... 
Calcium  .  .-,  ,"  v 
Magnesium  .  .  .j 
Iron  .  ^ 

.029 
.043 
.14 
.017 

.012 
.023 
.135 
.008 

.039 
.08 
.134 
.026 

.029 
.129 
.16 
.012 

.08 
.07 
.112 
.029 

.86 
.44 
.14 
.038 

1.14 

.77 
.13 
.144 

4.32 
1.40 
.63 
.38 

.053 
.39 
.163 
.038 

Phosphorus  .  .  . 
Sulfur  .  . 

.41 
.0032 

.29 

.0044 

.35 

.022 

.62 
.049 

.28 
.099 

.31 
.14 

.343 
.19 

.74 
.45 

.412 
.101 

Silicon  
Chlorine  

.018 
.006 

.014 
.013 

.57 
.029 

.011 
.065 

.036 
.131 

.06 
.25 

.031 
.66 

.35 
1.02 

.036 
.183 

*  Calculated  from  Wolff's  "Aschen  Analysen."  It  is  realized  that  more  modern 
methods  of  analysis  might  modify  the  above  figures  to  a  small  extent,  but  they 
are  sufficiently  accurate  for  illustration  of  the  variable  composition  of  the  ash  of 
different  species. 

26.  Elements   in   animals. — The   proportions   of   the 
chemical  elements  of  our  larger  animals  have  been  deter- 


22 


THE  FEEDING   OF  ANIMALS 


mined  through  analyses  made  of  the  entire  bodies  of 
steers  and  other  domestic  animals  by  Lawes  and  Gilbert, 
of  England,  and  the  Maine  Experiment  Station,  in  this 
country.  These  results,  combined  with  our  knowledge  of 
the  constitution  of  the  compounds  of  the  animal  tissues, 
enable  us  to  calculate  very  closely  the  proportion  of  car- 
bon and  other  elements  in  the  entire  body  of  an  ox: 

TABLE  III 


Fat  ox 
Lawes  &  Gilbert 

Two  steers,  2  yrs.old 
Maine  Station 

Carbon  

Per  cent 

63 

Per  cent 

60 

Oxygen  

13.8 

14.1 

Hydrogen  
Nitrogen  
Mineral  compounds  (ash)  .  .  . 

9.4 
5. 

8.8 

9. 
5.8 
11.1 

A  fat  ox  contains  a  much  larger  proportion  of  carbon 
than  a  lean  one,  because  the  fats  are  richer  in  carbon  than 
any  of  the  other  compounds  of  the  animal  body.  It  is 
seen  that  plants  and  animals  are  alike  in  containing  much 
more  of  carbon  than  of  any  other  element,  and  that  the 
quantities  of  the  remaining  elements  stand  in  the  same 
order  of  proportion  in  the  plant  and  in  the  animal, 
oxygen  being  in  greater  proportion  in  the  plant,  and  car- 
bon and  nitrogen  in  the  animal.  The  plant  and  animal 
are  alike,  therefore,  in  consisting  chiefly  of  elements 
derived  from  air  and  water.  Carbon,  oxygen,  and  hydro- 
gen constitute  from  83  to  86  per  cent  of  the  bodies  of  fat 
oxen.  It  follows  that  less  than  one-sixth  of  the  animal  is 
built  from  elements  that  have,  in  part,  a  commercial  value 
for  crop  production.  Nitrogen  and  certain  elements  in 
the  ash  of  the  plant  and  animal  bear  a  market  value. 


THE   CHEMICAL   ELEMENTS  23 

27.  Ash  elements  in  animal. — The  proportions  of  the 
ash  elements  are  shown  from  analyses  made  of  the  fat 
ox  by  Lawes  and  Gilbert.  For  comparison,  the  propor- 
tions of  ash  elements  in  the  human  body  are  given: 

TABLE  IV 


Ox 

Man 

Phosphorus  .'•;.'  

Percent 

1.53 
2.80 
.26 
.20 
.07 
3.29 
.65 

Percent 

1.13 
2.50 
.12 
.10 
.07 

.14 

Calcium 

Potassium                 

Sodium  .                                                                    .  '  . 

Magnesium                      

Oxvsren 

Silicon  and  sulfur                        

It  appears  that  in  the  ash,  other  than  oxygen,  phos- 
phorus and  calcium  take  a  leading  place  as  to  quantity, 
although  other  elements,  such  as  sulfur,  potassium,  and 
sodium  are  essential  to  animal  growth,  even  if  present  in 
relatively  small  amounts. 

28.  Classes  of  matter. — A  common  and  familiar 
phenomenon  is  the  destruction  of  vegetable  or  animal 
matter  by  combustion,  with  the  result  that  only  a  small 
portion  of  the  original  material  is  left  behind  in  visible 
and  solid  forms.  Fuel,  such  as  wood  or  coal,  is  largely 
consumed  when  ignited,  and  we  have  as  a  residue  the 
ash.  If  we  incinerate  hay,  corn,  or  wheat  we  get  a 
similar  result.  The  gradual  decomposition  of  exposed 
dead  vegetable  matter  that  occurs  in  warm  weather  is  a 
process  essentially  similar  to  the  combustion  of  fuel,  only 
more  prolonged.  In  view  of  these  facts,  it  is  customary 
to  classify  all  the  tissues  of  plants  and  animals  into  the 
combustible  and  incombustible  portions,  the  former  being 


24 


THE  FEEDING  OF  ANIMALS 


that  part  of  the  ignited  or  decayed  substance  which  dis- 
appears in  the  air  as  gases,  and  the  latter  the  residue 
or  ash. 

29.  Combustion  does  not  destroy  matter. — It  should 
be  well  understood  that  combustion  does  not  involve 
a  loss  of  matter;  only  a  change  into  other  forms.    If  we 
were  to  collect  the  gases  which  pass  off  from  a  stick  of 
wood  that  is  burned,  consisting  mostly  of  carbon  dioxid, 
vapor  of  water,  and  certain  compounds  of  nitrogen,  we 
would  find  that  their  total  weight,  plus  that  of  the  ash 
residue,  is  even  greater  than  that  of  the  dry  wood,  because 
the  carbon  and  the  hydrogen  of  the  wood  have  united 
during  the   combustion   with   an   increased   amount   of 
oxygen.   The  carbon,  oxygen,  hydrogen,  and  nitrogen  of 
the  plant  or  animal  tissue  belong  to  the  combustible 
portion,  although  small  amounts  of  two  of  these  elements 
are  found  in  the  ash,  as  it  is  usually  estimated.    The 
remainder  of  the  fifteen  elements  previously  named  is 
supposed  to  appear  wholly  in  the  ash,  although  in  different 
combinations  from  what  they  exist  in  the  plant. 

30.  Relation   of  combustible   to   incombustible   por- 
tions.— The  relation  in  quantity  of  the  combustible  and 
incombustible  parts  of  vegetable  and  animal  dry  matter 
is  illustrated  below: 

TABLE  V 


Combustible 

Incombustible 
(ash) 

Clover  hay    

Per  cent 
92.8 

Per  cent 
7.2 

Potato  tubers                                      .    . 

95.5 

4.5 

Maize  kernel      
Wheat  kernel 

98.3 
98. 

1.7 
2. 

Body  of  fat  ox   

91.2 

8.8 

THE   CHEMICAL  ELEMENTS  25 

The  significance  of  these  facts  in  their  relation  to 
cattle-feeding  is  that  the  chemical  change  which  we  call 
combustion  is  one  of  the  phenomena  of  animal  nutrition. 
Substances  which  may  suffer  either  slow  or  rapid  oxida- 
tion outside  the  animal  body  may  undergo  complete  or 
partial  combustion  in  the  animal;  or,  stated  in  another 
way,  the  part  of  the  plant  which  "burns  up"  in  the  fire- 
place or  crucible  is  the  part  which  in  general  undergoes 
the  same  change  within  the  animal  organism  in  so  far  as 
the  food  is  digested. 

31.  Organic  and  inorganic  classes. — The  terms  com- 
bustible and  incombustible  are  less  used,  perhaps,  than 
two  others  which  represent  practically  the  same  divisions 
of  plant  or  animal  substance,  viz.,  organic  and  inorganic. 
In  chemical  literature,  the  portion  of  a  plant  or  animal 
which  suffers  combustion  is  called  the  organic,  and  the 
ash  is  known  as  the  inorganic  part.  These  terms  were 
evidently  based  on  the  erroneous  assumption  that  the 
compounds  which  burn  and  break  up  into  simpler  ones 
are  peculiarly  those  which  sustain  necessary  and  vital 
relations  to  life,  and  are  formed  only  through  the  func- 
tions of  living  organisms.  To  be  sure,  the  dry  substance 
of  the  plant  is  organized  chiefly  by  building  up  com- 
pounds of  carbon,  oxygen,  hydrogen,  and  nitrogen,  which 
suffer  combustion;  but  compounds  of  sulfur,  phos- 
phorus, chlorine,  potassium,  sodium,  and  calcium  are 
also  constant  and  essential  constituents  of  the  juices  and 
tissues  of  the  plant  and  animal.  They  sustain  important 
relations  to  nutrition  and  growth.  It  is  true,  however, 
that  the  portion  of  a  food  material  which  is  commonly 
spoken  of  as  organic  embraces  those  compounds  that  fur- 
nish practically  all  the  energy  which  is  utilized  by  animal 
life  and  much  the  larger  part  of  the  building-material. 


CHAPTER  IV 
THE  COMPOUNDS  OF  ANIMAL  NUTRITION 

THE  animal  body  consists  primarily  of  elements,  but 
we  ordinarily  regard  it  as  made  up  of  compounds.  These 
are  groups  of  elements  united  in  such  fixed  and  con- 
stant proportions  that  they  have  as  uniform  properties, 
under  given  conditions,  as  the  elements  themselves.  In 
discussing  the  composition  and  uses  of  cattle  foods  and 
the  structure,  composition,  and  functions  of  the  animal 
as  an  organism,  we  refer  chiefly  to  the  compounds  of 
carbon  rather  than  to  carbon  itself.  In  the  language  of 
practice,  we  speak  of  proteins,  carbohydrates,  and  fats. 
Commerce  recognizes  these  compounds  also.  These  com- 
pounds are  the  source  of  the  energy  that  is  manifested  by 
animal  life,  and,  with  the  ash,  of  nearly  all  the  materials 
out  of  which  animal  tissues  are  built. 

32.  The  classes  of  compounds. — The  known  com- 
pounds that  belong  to  life  in  all  its  forms  are  almost 
innumerable.  These  sustain  a  variety  of  relations  to 
human  needs,  some  serving  as  food,  some  as  medicine,  and 
some  in  the  arts.  Comparatively  few  of  these  must  be 
considered  in  discussing  the  science  and  art  of  cattle- 
feeding.  Moreover,  the  compounds  which  play  a  leading 
part  in  animal  nutrition  are  designated,  especially  for 
practical  purposes,  in  classes  rather  than  singly,  which 
tends  to  more  or  less  looseness  of  expression  and  definition. 
For  instance,  the  popular  understanding  of  the  term  pro- 
tein doubtless  is  that  it  is  a  single  compound. 

(26) 


COMPOUNDS   OF  NUTRITION  27 

The  same  classification  is  used  for  the  compounds  of 
both  the  vegetable  and  animal  kingdoms,  which  are 
divided  into  the  following  groups : 

Water, 

Ash  (mineral  compounds), 

Protein  (nitrogenous  compounds), 

Carbohydrates  (and  related  bodies), 

Fats  (or  oils). 

Variously  named  compounds  partially  theoretical 
and  unclassified:  Enzyms,  antigens  hormones, 
vitamines  accessories,  activators.  (These  terms 
are  in  part  synonyms.) 

Accuracy  is  here  sacrificed  to  convenience.  These 
class  names  have  come  to  be  regarded,  more  or  less,  as 
representing  entities  having  fixed  properties  and  func- 
tions, whereas  each  class  contains  numerous  compounds 
differing  widely  in  their  characteristics  and  in  their  nutri- 
tive value  and  office.  Moreover,  these  terms  have  a 
variable  significance  as  used  under  different  conditions. 
No  one  of  them,  except  water,  uniformly  represents  just 
the  same  mixture  of  compounds  when  applied  to  unlike 
substances. 

33.  Distribution  of  elements. — It  is  well  to  gain  a 
clear  understanding  of  the  relation  which  the  fifteen 
elements  previously  mentioned  sustain  to  these  classes 
of  substances.  This  relation  can  be  shown  for  the  five 
main  classes  of  nutrients,  but  not  for  the  unclassified  or 
theoretical  bodies.  Just  what  elements  enter  into  these 
is  not  known.  So  far  as  known  they  do  not  have  a  con- 
structive function.  The  distribution  of  the  elements  can 
be  seen  most  readily  by  a  tabular  display: 


28 


THE   FEEDING  OF   ANIMALS 


All  vegeta- 
ble or  ani- 
mal matter 


Incombustible 
or  inorganic 
matter  . 


Water 


Ash 


Combustible 
or  organic 
matter  . 


Protein 


f  Oxygen 
\Hydrogen 

'Oxygen 
Sulfur 
Chlorine 
Phosphorus 
Silicon.    Fluorine 
Potassium 
Sodium 
Calcium 
Magnesium 
Iron 
Manganese 

Carbon 
Oxygen 
Hydrogen 
Nitrogen 
Sulfur  (generally) 
Phosphorus  (sometimes) 
Uron  (in  a  few  instances) 


Carbohydrates  f  Carbon 
and  fats.      .  J  Oxygen 

I  Hydrogen 


The  ash  which,  on  the  average,  constitutes  about  one- 
twentieth  of  the  plant,  and  never  more  than  one-tenth 
of  the  animal,  may  contain  thirteen  of  the  fifteen  ele- 
ments, while  the  larger  proportion  of  living  matter  con- 
sists mostly  of  the  compounds  of  three  or  four  elements, 
in  no  case  of  more  than  six  or  seven.  It  is  strikingly 
evident  that  the  dominant  elements  of  life,  quantity 
alone  considered,  are  those  derived  from  the  air  and  water. 


WATER 


Water  fills  a  very  important  place  in  agriculture.  All 
plant  substance,  all  animal  tissue,  foods,  and  nearly  all 
the  material  things  with  which  man  comes  in  contact  in 
his  daily  life  are  made  up  of  more  or  less  water,  or  are 


COMPOUNDS  OF  NUTRITION  29 

associated  with  it.  Sometimes  this  is  very  evident,  as 
with  green  plants  or  juicy  fruits.  It  is  not  so  evident 
with  straw  and  corn  meal.  If,  however,  we  submit 
almost  any  substance,  no  matter  how  dry  it  may  appear, 
except,  perhaps,  glass  and  metals,  to  the  heat  of  an  oven 
at  212°  F.,  we  find  that  a  material  loss  of  weight  occurs; 
and  if  we  so  arrange  that  whatever  is  driven  off  is  first 
drawn  through  some  substance  that  entirely  absorbs  the 
water  which  has  been  vaporized,  we  learn  that  the  decrease 
in  weight  is  nearly  all  accounted  for  by  the  water  thus 
collected. 

34.  Measurement   of   water-content. — This    suggests 
to  us  the  chemist's  way  of  determining  the  proportion  of 
water  which  any  particular  material  contains.   He  weighs 
out  a  certain  amount  of  the  substance  and  then  keeps  it 
in  an  oven  at  212°  F.  for  five  hours  perhaps,  after  which  it 
is  re-weighed.   The  difference  in  the  two  weights,  or  the 
loss,  is  assumed  to  be  all  water,  and  the  percentage  in  the 
original  substance  is  easily  calculated.    That  portion  of 
the  material  which  is  left  behind  after  the  water  is  evap- 
orated is  called  the  dry  substance. 

35.  Hygroscopic    water. — Water    is    associated    with 
plant  and  animal  substances  and  tissues  in  two  ways, 
hygroscopically  and  physiologically.    It  is  easy  to  illus- 
trate the  former  way.    If  an  ounce  of  corn  meal  were  to 
be  dried  in  an  oven  as  described,  it  would,  as  stated,  lose 
in  weight.    If  it  were  subsequently  allowed  to  remain 
exposed  in  the  open  air  in  a  barn  or  out-of-doors,  it  would 
regain  part  or  all  of  its  original  weight.   The  loss  would 
be  due  to  water  driven  away  by  heat,  and  the  gain  to 
water  absorbed   from   the   atmosphere,  which   we  call 
hygroscopic  moisture. 

All  solids  attract  moisture  up  to  a  certain  proportion 


30  THE  FEEDING  OF  ANIMALS 

which  varies  with  the  substance  and  with  the  conditions 
that  prevail.  The  surfaces  of  the  particles  of  matter  are 
ordinarily  covered  with  a  thin  film  of  water,  which  is 
thicker  on  a  cold,  wet  day  than  on  a  warm,  dry  day,  and 
so  the  same  quantity  of  hay  or  gram  weighs  less  at  one 
time  than  at  another,  because  the  percentage  of  hygro- 
scopic water  varies.  An  equilibrium  will  always  be  estab- 
lished between  the  attraction  of  a  substance  for  moisture 
and  the  tension  of  the  vapor  of  water  in  the  surrounding 
air,  which  accounts  for  the  effect  of  temperature  and  of 
the  degree  to  which  the  air  is  saturated  with  water- vapor. 
As  all  substances  do  not  have  the  same  attraction  for 
moisture,  therefore,  under  similar  atmospheric  conditions, 
one  feeding-stuff  may  retain  more  water  than  another. 

36.  Physiological  water. — Water  that  is  held  physio- 
logically is  that  which  is  a  constant  and  essential  part  of 
living  organisms,  in  which  relation  it  is  necessary  to  life 
and  performs  certain  important  functions.    These  func- 
tions are  of  three  kinds:  (1)  The  presence  of  water  in  the 
tissues  of  plants  and  animals  gives  them  more  or  less  firm- 
ness or  rigidity  combined  with  elasticity;  (2)  water  acts 
as  a  food-solvent;  (3)  water  is  the  great  carrier  of  food 
materials  and  of  waste  products  from  one  part  to  another 
of  the  vegetable  or  animal  organism. 

37.  Water  in  living  plants. — Water  constitutes  a  large 
proportion  of  the  weight  of  all  living  plants,  especially 
during  the  period  of  active  growth.  The  cured  hay  weighs 
much  less  than  did  the  green  grass  when  it  was  cut,  and 
this  loss  in  weight  is  due  almost  wholly  to  evaporation  of 
water  from  the  tissues  of  the  plant  under  the  influence  of 
the  sun  and  wind.   This  water,  which  is  contained  in  the 
cells,  tubes,  and  intercellular  spaces  of  the  stalk  or  leaf,  is 
pure  water  and  has  no  more  physiological  value  for  the 


COMPOUNDS  OF  NUTRITION  31 

animal  than  water  from  any  other  source  excepting  that 
it  is  pure  and  is  not  subject  to  the  contamination  which 
sometimes  occurs  in  streams  and  wells.  There  is  no  such 
thing  as  the  so-called  natural  water  of  plants,  which  has 
a  peculiar  nutritive  value  or  function. 

38.  Sap  or  plant  juice. — Vegetation  water  should  be 
distinguished  from  sap  or  plant  juice.  Sap  is  more  than 
water;  it  is  water  holding  in  solution  certain  substances 
such  as  sugars  and  mineral  salts.  When  the  plant  is 
dried,  these  soluble  compounds  do  not  pass  off,  but  remain 
behind  as  part  of  the  dry  matter. 

39.  Proportion  of  water  in  plants. — The  proportion  of 
water  in  plants  varies  greatly  in  different  species,  and  in 
the  same  species  according  to  the  stage  of  growth  or  the 
surrounding  conditions.  These  facts  have  more  impor- 
tance than  is  generally  recognized,  because  the  food 
value  of  vegetable  substances  is  largely  determined  by  the 
proportion  of  dry  matter.  It  is  always  necessary  to  know 
the  percentage  of  water  in  a  green  plant  before  we  can 
estimate  its  worth  for  feeding  purposes. 

The  variations  in  water-content  of  the  living  tissues  of 
different  species  of  plants  or  parts  of  plants  are  well  illus- 
trated by  the  following  average  figures:  (See  Pars.  304- 
306.) 

TABLE  VI.    WATER  IN  GREEN  PLANTS         Percent 

Pasture  grass  (mixed) (".v  .,..'..'       80. 

Timothy  grass -   .   .    .    ,    .       61.6 

Oats  (fodder)      '.    .    .    .    .    .   .  <.    .       62.2 

Rye  (fodder)      -..' .    .  v 76.6 

Sorghum  (fodder)      79.4 

Fodder  corn,  dent,  kernels  glazed       73.4 

Red  clover 70.8 

Alfalfa 71.8 

Horse-bean 84.2 

Potatoes  (tubers)       78.9 

Turnips 90.5 


32  THE  FEEDING  OF  ANIMALS 

40.  Effect  of  stage  of  growth  on  water-content. — 
Immature  plants  contain  more  water  than  older  or  mature 
ones.  Young  pasture  grass  is  more  largely  water  than  the 
same  plants  would  be  after  the  seed  is  formed.  This  fact 
is  consistent  with  the  very  rapid  transference  of  building- 
material  during  the  active  stages  of  growth.  Analyses  of 
samples  of  timothy  grass  cut  at  the  Maine  State  College, 
in  1879,  and  at  the  Pennsylvania  State  College,  in  1881, 
show  the  marked  influence  of  the  stage  of  growth  on 
the  water-content  of  the  living  plant: 

TABLE  VII.    TIMOTHY 
Maine  State  College  P5°watJ? 

Nearly  headed  out 78.7 

In  full  blossom       71.9 

Out  of  blossom       65.2 

Nearly  ripe 63.3 

Pennsylvania  State  College      Percentage  of  water 

Highly  No 

manured       manure 

Cut  June  6,  heads  just  appearing  .  .  .  79.7  76.5 
Cut  June  23,  just  beginning  to  bloom  .  69.7  69.1 
Cut  July  5,  somewhat  past  full  bloom  .  61.4  60. 

What  is  true  of  timothy  is  probably  true  of  all  forage 
crops  in  the  perfectly  fresh  state.  We  have  here  an  expla- 
nation of  the  difficulty  of  curing  early  cut  grass.  When 
the  farmer  begins  haying,  at  least  two  drying  days  are 
needed  in  order  to  secure  a  product  that  will  not  ferment 
in  the  mow,  while  later  in  the  season,  grass  cut  in  the 
morning  may  be  safely  stored  in  the  mow  before  night. 
At  the  Maine  State  College,  in  1880,  immature  timothy 
grass  lost  56.7  per  cent  weight  in  curing  and  the  ripe 
grass  only  12.9  per  cent.  The  extreme  succulence  of 
immature  corn  and  other  crops  previous  to  the  formation 
of  seed  is  a  fact  which  the  dairyman  who  feeds  soiling- 


COMPOUNDS  OF  NUTRITION  33 

crops  must  consider  if  he  would  uniformly  maintain  a 
ration  up  to  the  desired  standard. 

41.  Influence   of   soil  moisture. — The  proportion  of 
water  in  plants  is  influenced  also  by  the  lack  or  excess  of 
soil  moisture.    The  soil  and  not  the  atmosphere  is  the 
source  of  supply  of  vegetation  water,  which,  taken  up  by 
the  roots,  traverses  the  plant  and  passes  into  the  atmos- 
phere through  the  leaves.    If  the  supply  is  abundant,  the 
tissues  are  constantly  fully  charged,  but  if,  by  reason  of 
drought,  the  soil  becomes  very  dry,  the  outgo  of  water 
by  evaporation  may  exceed  the  income.  During  a  drought 
vegetation  water  often  falls  below  the  normal,  or  below 
what  is  necessary  to  maintain  the  tissues  in  their  usual 
condition  of  rigidity  or  to  perform  fully  their  physio- 
logical functions. 

42.  Supply  of  water  to  plants. — This  leads  to  the 
observation  that  the  water  in  a  growing  plant  is  that 
which  is  in  transit  from  the  soil  to  the  air.    This  liquid 
stream  enters  the  plant  with  its  load  of  building-materials, 
takes  into   solution  the  compounds  elaborated  in   the 
leaves  and  aids  in  transporting  them  to  the  points  of 
rapid  growth,  finally  passing  into  the  air  from  the  sur- 
face of  the  foliage.    Throughout  the  entire  growing  sea- 
son the  plant  acts  as  a  pump,  drawing  from  below  through 
the  roots  the  water  which  it  needs  for  various  purposes, 
and  discharging  it  into  the  air.    It  was  found  that  in 
Wisconsin  309.8  tons  of  water  were  evaporated  by  the 
plant  for  each  ton  of  dry  matter  in  the  crop.  Four  tons  of 
dry  matter  to  the  acre  is  not  an  unusual  product  with 
maize,  requiring  1,239.2  tons  or  10.4  inches  of  water  for 
its  growth,  the  equivalent  of  about  five-eighteenths  of  an 
average  annual  rainfall.  This  is  a  fact  of  great  significance 
to  the  stock-feeder.    His  success  begins  with  proper  hus- 

c 


34  THE  FEEDING  OF  ANIMALS 

banding  of  the  plant-food  resources  of  the  farm,  of  which 
water  is  an  important  factor. 

43.  Water  in  feeding-stuffs.— Cattle  foods,  whether 
in  the  green  or  air-dry  condition,  always  contain  more 
or  less  water.   The  proportion  is  greatly  variable,  depend- 
ing upon  several  factors.   With  the  green  foods,  the  range 
of  percentages  is  similar  to  that  of  the  living  plants  pre- 
viously noted.   As,  however,  forage  plants  are  used  at 
varying  lengths  of  time  after  cutting,  and  as  a  loss  of 
moisture  begins  immediately  after  the  plant  is  severed 
from  its  source  of  water-supply,  the  amount  of  dry  matter 
in  a  green  forage  crop  is  somewhat  uncertain,  unless  a 
water-determination  is  made  in  the  material  exactly  as 
it  is  fed.    In  all  experimental  work  this  precaution  is 
necessary  to  accuracy.    Roots  and  potatoes  contain  a 
large  proportion  of  water,  which,  owing  to  their  struc- 
ture, is  slowly  evaporated.    In  a  cool,  moist  cellar,  their 
water-content  will  remain  practically  unchanged  for  a 
long  time;  in  a  warm,  dry  room,  evaporation  occurs  and 
they  shrivel  and  lose  weight. 

44.  Conditions    affecting    water-content    of   feeds. — • 
The  water-content  of  air-dry  foods  varies  with  the  con- 
dition in  which  they  were  stored,  the  length  of  time  after 
storage,  and  the  percentage  of  moisture  in  the  air.   Early 
cut  hay  often  goes  to  the  barn  less  perfectly  cured  than 
the  late  cut,  and  all  hay  dries  out  more  than  is  generally 
realized  during  the  first  few  months  of  storage.    Con- 
cerning these  points,  the  writer  has  obtained  data  through 
experiments  at  the  Maine  State  and  Pennsylvania  State 
colleges.   Fourteen  lots  of  hay,  some  early  cut  and  some 
late  cut,   were   weighed   when   stored   and   again   after 
remaining  in  the  barn  for  several  months.    The  results 
follow: 


COMPOUNDS  OF  NUTRITION 


35 


TABLE  VIII 


Early 

Early 

nu+ 

Late 

Late  cut 

cut 

cut 
after 

Per  cent 

cut 

after 

Percent 

as 

loss 

as 

several 

loss 

stored 

months 

stored 

months 

Pounds 

Pounds 

Pounds 

Pounds 

Timothy     ....    1881 

3634 

2307 

36.5 

4234 

3390 

19.9 

Timothy     ....    1882 

3634 

2556 

29.7 

3802 

3168 

16.7 

Timothy     ....    1881 

5000 

3922 

21.6 

5270 

4035 

23. 

Timothy     ....    1882 

3570 

3037 

14.9 

4017 

3413 

15. 

Clover     1882 

2110 

1215 

42.4 

1520 

1130 

25.6 

Timothy     ....    1888 

2815 

2470 

12.2 

2790 

2420 

13.3 

Timothy     ....    1889 

5070 

4225 

16.6 

6208 

5086 

18.1 

Average      .    .    . 

24.9 

18.8 

General  average  loss,  22.2  per  cent. 

It  is  probable  that  hay  seldom  loses  less  than  one- 
eighth  of  its  weight  during  storage,  and  often  much  more. 

As  illustrating  the  variations  in  the  proportions  of 
water  in  hay  due  to  changes  in  air  moisture,  reference  is 
made  to  observations  by  Atwater.  He  found  that  dry 
hay  hung  in  bags  in  a  barn  varied  in  water-content 
between  7.5  per  cent  and  13.6  per  cent  during  the 
months  of  May,  June,  and  July.  Hay  in  large  masses 
would  change  less,  but  would  be  affected,  doubtless,  by 
long  periods  of  very  dry  weather  or  very  wet. 

45.  Relation  of  water  to  preservation  of  cattle  foods. — 
Tbe  proportion  of  moisture  in  coarse  foods  and  grains 
has  much  to  do  with  their  preservation  in  a  sound  con- 
dition. New  hay  and  grains  when  packed  in  large  masses 
are  subject  to  fermentations  which  injure  their  quality 
and  diminish  their  food  value.  This  is  due  to  the  fact  that 
sufficient  moisture  is  present  to  allow  the  growth  of  low 
forms  of  life  with  certain  attendant  chemical  changes. 
Feeding-stuffs  containing  20  per  cent  or  more  of  water—- 
and this  is  likely  to  be  the  case  with  clover,  rowen,  field- 


36  THE  FEEDING  OF  ANIMALS 

cured  corn  fodder  and  stover,  new  oats  and  new  corn — 
when  stored  in  large  quantities  are  almost  certain  to  heat 
and  become  musty  or  moldy,  always  involving  a  loss  of 
nutritive  value.  (See  Par.  306.) 

46.  Water  in  the  animal. — Water  is  an  important  and 
abundant  constituent  of  animal  organisms,  from  the 
lowest  to  the  highest  forms.  The  blood,  which  is  from 
one-thirtieth  to  one-twentieth  the  weight  of  the  bodies  of 
farm  animals,  is  at  least  four-fifths  water,  while  the  soft 
tissues  have  been  found  to  contain  from  44  to  75  per 
cent,  according  to  the  species,  age,  and  condition  of  the 
animal.  The  most  extensive  and  complete  analyses  so 
far  made  of  the  entire  bodies  of  animals  were  performed 
by  Lawes  and  Gilbert  at  Rothamsted,  England.  In  this 
country,  four  steers  were  analyzed  at  the  Maine  Experi- 
ment Station,  and  in  the  study  of  human-nutrition 
problems  many  determinations  of  water  have  been  made : 

TABLE  IX.    WATER  IN  ENTIRE  BODY  per  cent 

Ox,  well  fed,  Lawes  &  Gilbert 66.2 

Ox,  half  fat,  Lawes  &  Gilbert 59. 

Ox,  fat,  Lawes  &  Gilbert 49.5 

Steer,  17  months  old,  medium  fat,  Me.  E.  S 59. 

Steer,  17  months  old,  medium  fat,  Me.  E.  S 56.3 

Steer,  27  months  old,  fat,  Me.  E.  S 51.9 

Steer,  27  months  old,  fat,  Me.  E.  S 52.2 

Calf,  fat,  Lawes  &  Gilbert 64'.6 

Sheep,  lean,  Lawes  &  Gilbert      67.5 

Sheep,  well  fed,  Lawes  &  Gilbert 63.2 

Sheep,  half  fat,  Lawes  &  Gilbert 58.9 

Sheep,  fat,  Lawes  &  Gilbert 50.9 

Sheep,  very  fat,  Lawes  &  Gilbert 43.3 

Swine,  well  fed,  Lawes  &  Gilbert 57.9 

Swine,  fat,  Lawes  &  Gilbert 43.9 

Chicken,  flesh 74.2 

Fowl,  flesh 65.2 

Goose,  flesh 42.3 

-  Turkey,  flesh      .    :    .    .    :    .    .    .    . '.    ...   v  .    .    .  55.5 


COMPOUNDS   OF  NUTRITION  37 

It  is  very  evident  that,  in  general,  considerably  more 
than  half  of  the  weight  of  the  bodies  of  our  domestic  ani- 
mals consists  of  water,  the  limits  observed  in  all  species 
and  conditions  here  mentioned  being  42.3  and  74.2 
per  cent. 

47.  Variations  of  water-content  of  animal  bodies. — 
The  percentage  of  water  varies  with  the  species,  age,  and 
condition.  Swine  carry  a  notably  small  proportion.  The 
calf's  body,  even  though  fat,  is  comparatively  watery. 
It  is  very  noticeable  that  with  oxen,  sheep,  and  swine  the 
lean  animals  contain  a  much  larger  proportion  of  water 
than  the  fat.  This  does  not  necessarily  mean  that  in  the 
process  of  fattening  the  fat  is  substituted  for  water,  and 
so  expels  it  from  the  organism,  but  that  the  increase  has 
a  much  smaller  percentage  of  water  than  the  body  in  its 
original  lean  condition.  This  is  well  illustrated  by  the 
data  from  two  independent  investigations  at  Rothamsted 
and  at  the  Maine  Experiment  Station.  The  former  investi- 
gation showed  that  when  swine,  sheep,  and  oxen  were 
fattened  the  increase  contained  from  20  to  24  per  cent 
of  water,  this  being  half  the  proportion  found  in  the  entire 
bodies  of  the  lean  animals.  The  Maine  Station  results 
established  the  fact  that  in  the  increase  of  two  steers 
from  the  age  of  seventeen  to  twenty-seven  months,  dur- 
ing which  time  a  fattening  ration  was  fed,  there  was  42 
per  cent  of  water,  the  bodies  of  the  younger  steers  hav- 
ing 58.2  per  cent.  It  is  a  common  remark  among  unscien- 
tific people  that  beef  from  mature  animals  "spends" 
better  than  that  from  young,  the  same  observation  being 
made  in  comparing  lean  and  fat  beef.  Modern  investiga- 
tion shows  clearly  that  the  reason  for  this  lies  partly  in 
the  difference  in  water-content.  Dry  matter,  and  not 
water,  is  the  measure  of  food  value. 


38  THE  FEEDING  OF  ANIMALS 

ASH 

The  ash  or  mineral  part  of  plants  and  animals  has 
occupied  a  minor  place  in  the  discussions  which  pertain 
to  the  principles  and  problems  of  animal  nutrition.  In  the 
past  chief  attention  has  been  given  to  the  carbon  com- 
pounds of  living  organisms,  while  the  compounds  of  the 
mineral  world,  in  their  relation  to  foods  and  to  nutritive 
processes,  have  generally  been  passed  by  with  too  brief 
discussion.  It  is  desirable  to  gain  a  clear  understanding 
of  the  combinations,  distribution,  and  functions  of  the 
constituents  of  the  ash,  for  their  importance  in  animal 
nutrition  is  no  less  than  pertains  to  the  carbon  compounds. 

48.  Mineral  compounds  in  the  ash  of  plants  and 
animals. — As  previously  stated,  the  mineral  portion  of  a 
plant  or  animal  is  measured  by  the  ash  or  residue  after 
combustion,  the  principal  ingredients  of  which  are  the 
following: 

TABLE  X 
Adds  Bases 

Hydrochloric  acid   .    .    .  HC1.         Potash      K2O 

Sulfuric  acid H2SO4       Soda Na^O 

Phosphoric  acid       .    .    .  H6P2C>8      Lime      CaO 

Silicic  acid SiO2          Magnesia      MgO 

Carbonic  acid      ....  CO2          Iron  oxid      Fe2O3 

Other  mineral  compounds  are  found  in  the  various 
forms  of  vegetable  life,  but  those  mentioned  are  all  that 
we  need  to  discuss  at  length. 

The  acids  and  bases  do  not  exist  in  the  ash  as  shown, 
but  they  are  united  to  form  salts,  and  so  we  have  the 
chlorides,  sulfates,  phosphates,  and  carbonates  of  potas- 
sium, sodium,  calcium,  magnesium,  and  iron.  These 
are  nearly  all  familiar  objects  in  common  life,  as,  for 
instance,  sodium  chloride  (common  salt),  potassium 


COMPOUNDS   OF  NUTRITION  39 

chloride  (the  muriate  of  potash  of  the  market),  potassium 
sulfate  (the  sulfate  of  potash  of  the  market),  calcium  sul- 
fate  (of  which  gypsum  or  land-plaster  is  composed),  cal- 
cium phosphate  (burned  bone  is  chiefly  this  compound), 
potassium  phosphate  (a  compound  of  phosphoric  acid 
and  potash  found  chiefly  at  the  druggist's),  and  calcium 
carbonate  (limestone). 

49.  Rearrangement  of  ash  elements  during  ignition. — 
It  should  be  remembered  that  the  compounds  in  the  ash 
are  not  necessarily  those  of  the  plant  or  animal.   During 
the  ignition  of  plant  or  animal  substance,  organic  com- 
pounds are  broken  up,  certain  acid  and  basic  elements  of 
which  enter  into  other  combinations  in  the  salts  of  the 
ash.  Much  of  the  lime  in  the  ash  is  in  union  with  carbonic 
acid,  which  in  the  plant  may  have  been  associated  with 
vegetable  acids,  such  as  oxalic  and  tartaric,  and  part  of 
the  sulfur  and  phosphorus  of  the  ash  comes  from  cer- 
tain carbon  compounds. 

The  salts  of  the  ash  differ  greatly  in  their  properties. 
Some  are  soluble  hi  water,  others  are  not.  To  the  former 
class  belong  all  the  chlorides,  and  the  potassium  and 
sodium  sulfates  and  phosphates.  The  normal  phosphates 
of  calcium  and  magnesium  are  insoluble  in  water,  but 
soluble  in  various  acids.  These  facts  are  important  in 
showing  what  salts  may  be  found  in  the  plant  and  animal 
juices,  and  what  effect  leaching  with  water  or  other  sol- 
vents might  have  on  the  inorganic  portion  of  cattle  foods. 

50.  The  ash  compounds  of  plants. — Upon  incinera- 
tion, all  plants  and  feeding-stuffs  yield  an  ash  residue 
which  has  been  termed  the  mineral  part  of  the  plant.  The 
ash  elements  are  important  in  this  connection  because 
they  are  the  main  source  of  the  same  elements  of  the 
animal  body.   These  may  be  held  in  plant  tissue  in  three 


40 


THE  FEEDING  OF  ANIMALS 


ways:  in  organic  combinations  and  as  the  inorganic  salts 
of  plant  solutions,  crystals  and  incrustations.  Outside 
of  phosphorus  and  sulfur,  little  is  known  of  the  relations 
to  plant  structure  of  the  important  ash  elements,  such  as 
potassium,  calcium,  and  magnesium.  Their  place  as 
bases  in  organic  structures  is  not  fully  understood. 

51.  Variations  of  plant  ash. — The  ash  from  different 
plants  and  feeding-stuffs  is  by  no  means  uniform  in  com- 
position and  quantity,  even  in  the  same  species  or  class 
of  materials,  although  with  the  grains  there  is  some  degree 
of  uniformity  in  this  respect.   Certain  factors  cause  varia- 
tions, such  as  species,  stage  of  growth,  fertility,  the  part 
of  the  plant,  and  changes  due  to  manufacturing  processes. 

52.  Variations  of  ash  due  to  species. — Different  species 
of    plants,    and    consequently    different    feeding-stuffs, 
are  greatly  unlike  in  their  content  of  mineral  matter. 
The  figures  of  Table  XI  illustrate  this  fact: 

TABLE  XI 


Number  of 
analyses 

Per  cent 
ash 

Mixed  grasses        
Timothy  grass 

106 
9 

7. 

6.8 

English  ray  grass      .        .... 

11 

12.1 

Red  clover,  in  bloom        
Seradella,  in  bloom       

113 
3 

6.9 

9.8 

Buckwheat 

17 

8.2 

Potatoes     ....           

59 

3.8 

Sugar-beets    

149 

3.8 

Turnips       

32 

8. 

Carrots 

11 

5.8 

Winter  wheat    

110 

2. 

Oats                                                         .... 

57 

3.1 

Maize 

15 

1.4 

Field  beans                                           

19 

3.6 

COMPOUNDS  OF  NUTRITION 


41 


As  a  rule  forage  crops  contain  a  higher  percentage  of  ash 
than  do  the  grains.  These  variations  pertain  not  alone  to 
the  quantity  of  ash  but  to  the  proportions  of  compounds 
which  it  contains: 

TABLE  XII.  THE  MINERAL  COMPOUNDS  OP  PLANTS  AND  FEEDING- 
STUFFS  (PER  CENT  IN  THE  DRY  MATTER) 


Potash 

o3 

I 

a 

Magnesia 

! 

g 

1 

l! 
*r 

.s 

.§1 
1* 

8 

1 

Chlorine 

Mixed  grasses        .    .    . 

1.86 

.20 

1.11 

.48 

.11 

.50 

.36 

2. 

.43 

Timothy  hay         .    .    . 

2.37 

.12 

.55 

.22 

.06 

.80 

.19 

2.19 

.35 

Red  clover  in  bloom     . 

2.21 

.13 

2.39 

.75 

.07 

.66 

.22 

.18 

.26 

White  clover         .    .    . 

1.57 

.53 

2.21 

.69 

.15 

.94 

.54 

.33 

.31 

Alfalfa    

1.74 

.13 

3. 

.36 

.14 

.63 

.42 

.70 

.22 

Buckwheat    .        ... 

2.54 

.19 

3.32 

1.09 

.12 

.50 

.30 

.09 

.06 

Roots 

Potatoes     

2.27 

.11 

.10 

.19 

.04 

.64 

.25 

.08 

.13 

Sugar-beets    

2.03 

.34 

.23 

.30 

.04 

.47 

.16 

.09 

.18 

Fodder  beets      .    .    .    . 

3.96 

1.23 

.28 

.83 

.06 

.65 

.23 

.15 

.75 

Turnips  

3.64 

.79 

.85 

.30 

.06 

1.02 

.90 

.15 

.41 

Carrots       

2.02 

1.16 

.62 

.24 

.05 

.70 

.35 

.13 

.25 

Grain 

Winter  wheat    .    .    .    . 

.61 

.04 

.06 

.24 

.03 

.93 

.01 

.04 

Oats 

.56 

.05 

.11 

.22 

.04 

.80 

.06 

1.22 

.03 

Summer  barley     .    .    . 

.56 

.06 

.07 

.23 

.03 

.92 

.05 

.68 

.03 

Maize  kernel     .... 

.43 

.02 

.03 

.22 

.01 

.66 

.01 

.03 

.01 

Peas    

1.18 

.03 

.13 

.22 

.02 

.98 

.09 

.02 

.04 

Field  beans    

1.51 

.04 

.18 

.26 

.02 

1.41 

.12 

.02 

.06 

These  figures  show  that  potash,  lime,  magnesia,  and 
phosphoric  acid  are  the  prominent  mineral  compounds 
of  the  plant  ash,  and  it  is  with  them  that  we  find  the 
important  variations.  The  true  grasses  differ  from  the 
clovers  and  related  plants  in  containing  much  less  lime 
and  greatly  more  silica,  the  phosphoric  acid  and  potash 
not  being  greatly  unlike  in  the  two  cases.  As  a  source  of 
lime,  then,  the  clover  hay  is  superior.  Potatoes  and  roots 
have  an  ash  richer  in  potash  and  poorer  in  lime  than  are 


42 


THE   FEEDING  OF  ANIMALS 


the  coarse  fodders.  The  grains  with  hulls  contain  much 
silica,  and  those  like  wheat  and  corn  but  little.  The  seeds 
of  the  legumes  are  richer  in  potash  and  lime  than  those 
of  the  grasses.  The  maize  kernel  is  especially  poor  in 
lime. 

53.  The  distribution  of  mineral  compounds  in  the  dif- 
ferent parts  of  the  plant. — Because  the  farmer  separates 
his  crops  into  grain  and  straw,  and  the  manufacturer  goes 
farther  and  divides  the  grain  into  parts,  thus  modifying 
the  character  of  feeding-stuffs,  especially  by-products, 
it  is  necessary  to  consider  just  how  the  mineral  compounds 
are  distributed  in  the  .stalk,  leaves,  and  fruit,  especially 
of  the  cereal-grain  plants.  A  comparison  of  the  straws 
and  grains  shows  striking  dissimilarities: 

TABLE  XIII.    PER  CENT  IN  THE  DRY  MATTER 


" 

12 

1 

1 

1 

1 

.2 

| 

a 

+•» 

1 

o3 

OJ 

o 

§^ 

1 

03 

3 

3 

I 

1 

3 

1 

& 

£* 

i 

1 

6 

Wheat- 

Straw    .... 

5.4 

.73 

.07 

.31 

.13 

.03 

.26 

.13 

3.62 

.09 

Kernel      .    .    . 

2. 

.61 

.04 

.06 

.24 

.03 

.93 

.01 

.04 

Oats- 

Straw    .... 

7.2 

2.07 

.24 

.50 

.26 

.08 

.33 

.23 

3.34 

.31 

Kernel      .    .    . 

3.1 

.56 

.05 

.11 

.22 

.04 

.80 

.06 

1.22 

.03 

Maize  — 

Straw    .... 

5.3 

1.93 

.06 

.58 

.30 

.12 

.44 

.28 

1.53 

.07 

Kernel      .    .    . 

1.4 

.43 

.02 

.03 

.22 

.01 

.66 

.01 

.03 

.01 

Peas  — 

Straw    .... 

5.1 

1.17 

.21 

1.89 

.41 

.09 

.41 

.32 

.35 

.29 

Kernel      .    .    . 

2.7 

1.18 

.03 

.13 

.22 

.02 

.98 

.09 

.02 

.04 

The  straws  contain  more  mineral  matter  than  the 
grains.  In  the  straws  there  is  much  more  potash,  lime, 
and  silica  than  in  the  grains,  while  phosphoric  acid  exists 
in  larger  proportions  in  the  latter. 


COMPOUNDS  OF  NUTRITION 


43 


The  roots  and  leaves  of  beets  and  turnips  present  a 
striking  difference  in  mineral-content: 

TABLE  XIV.    PER  CENT  IN  THE  DRY  MATTER 


T3 

<D 

.2 

'3 

jt 

1 

•§ 

| 

o 

0) 

1 

c3 

• 

1 

° 

o'§ 

1 

g 

| 

. 

1 

1 

1 

3 

£ 

£" 

3 

02 

1 

Sugar-beets  — 

Roots    .... 

3.8 

2.03 

.34 

.23 

.30 

.04 

.47 

.16 

.09 

.18 

Leaves      .    .    . 

14.8 

3.90 

2.05 

3. 

1.69 

.08 

.71 

.79 

1.51 

1.26 

Fodder  beets- 

Roots   .... 

7.6 

3.96 

1.23 

.28 

.83 

.06 

.65 

.23 

.15 

.75 

Leaves      .    .    . 

15.3 

4.71 

2.98 

1.63 

1.46 

.22 

1. 

.86 

.56 

2.45 

Turnips  — 

Roots    .... 

8. 

3.64 

.79 

.85 

.30 

.06 

1.02 

.90 

.15 

.41 

Leaves     .    .   . 

11.6 

2.73 

1.10 

3.83 

.46 

.18 

.85 

1.09 

.45 

1.18 

There  appears  to  be  a  tendency  for  mineral  compounds 
to  accumulate  in  the  leaves  of  plants,  and  leafy  plants 
are,  as  a  rule,  those  which  appropriate  these  most  freely. 

The  ash  of  the  outside  of  the  stem  and  of  the  husks  of 
seeds  is  in  relatively  large  proportions,  due  sometimes  to 
an  excess  of  silica.  Husked  rice  kernels  contain  not  over  .5 
per  cent  of  ash,  while  the  husks  contain  39  per  cent  or  over. 

54.  Influence  of  manufacturing  processes  on  the  ash 
constituents. — The  cattle-food  market  is  abundantly 
supplied  with  by-products  from  certain  manufacturing 
industries,  such  as  milling,  brewing,  and  starch  produc- 
tion. One  prominent  by-product  is  wheat  bran.  As  this 
is  the  outside  of  the  kernel,  we  would  naturally  expect, 
in  view  of  the  previous  statements,  that  it  would  be  rich 
in  mineral  compounds,  and  we  find  such  to  be  the  case. 
The  wheat  kernel  contains  about  2  per  cent  of  ash,  wheat 
bran  about  6  per  cent,  and  wheat  flour  about  .5  per  cent. 
Bran  is  rich  in  needed  mineral  compounds. 


44 


THE  FEEDING   OF  ANIMALS 


In  brewing,  the  kernels  of  barley  are  subjected  to  a 
leaching  process  which  results  in  taking  out  the  soluble 
mineral  salts,  chiefly  the  salts  of  potassium,  calcium,  and 
sodium,  leaving  behind,  in  part,  the  compounds  of  lime 
and  magnesium.  This  fact  is  made  clear  by  comparing  the 
analysis  of  the  ash  of  barley  with  that  of  brewers'  grains : 

TABLE  XV.    PARTIAL  COMPOSITION  OF  ASH  (PER  CENT) 


Potash 

Soda 

Lime 

Mag- 
nesia 

Phos- 
phoric 
acid 

Summer  barley    .    

.56 

.06 

.07 

.23 

.92 

Brewers'  grains        .        .    . 

.15 

.64 

.45 

1  69 

As  a  source  of  phosphoric  acid  and  lime  the  brewers' 
grains  are  more  efficient,  pound  for  pound,  than  the 
original  barley  grains. 

55.  The  mineral  compounds  of  animal  bodies. — The 
mineral  compounds  of  animals  are  nearly  similar  in  kind 
to  those  of  plants,  but  are  very  different  in  relative  pro- 
portions. This  is  made  plain  by  a  comparison  of  the 
figures  given  below: 

TABLE  XVI.    ASH  IN  PLANTS  AND  ANIMALS 


o 

1 

'1 

J 

0 

.§ 

1 

1 

i 

| 

1 

.-C 

| 

c3 
W 

2 

H 

& 

to 

'3 

^ 

AH 

CQ 

a 

O 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Dry  substance 

cent 

cent 

cent 

cent 

cent 

cent 

cent 

cent 

cent 

Timothy  hay     .    .    . 

6.8 

2.4 

.12 

.55 

.22 

.80 

.19 

2.2 

.35 

Maize  kernel     .    .    . 

1.4 

.43 

.02 

.03 

.22 

.66 

.01 

.03 

.01 

Wheat  kernel     .    .    . 

2. 

.61 

.04 

.06 

.24 

.93 

.01 

.04 

Fresh  bodies  — 

Fat  ox     

3.9 

.14 

.12 

1.74 

.05 

1.56 

.01 

Fat  sheep       .... 

2.9 

.14 

.13 

1.19 

.04 

1.13 

.02 

Fat  swine       .... 

1.8 

.10 

.07 

.77 

.03 

.73 

COMPOUNDS  OF  NUTRITION  45 

Potash  is  much  less  prominent  in  the  composition  of 
the  animal  than  is  the  case  with  plants,  and  phosphoric 
acid  and  lime  are  much  more  so.  In  general,  more  than 
80  per  cent  of  the  ash  of  the  animal  body  consists  of  phos- 
phoric acid  and  lime  in  combination  as  calcium  phosphate, 
whereas  these  two  compounds  constitute  less  than  one- 
fifth  of  the  ash  of  hay  and  less  than  one-half  of  the  ash 
of  maize  and  wheat  kernels. 

56.  The  distribution  of  inorganic  compounds  in  the 
animal  body. — The  bones  contain  a  very  large  proportion 
of  the  ash  constituents  found  in  the  animal  body,  the  soft 
parts  being  poor  in  mineral  salts.  Between  60  and  70 
per  cent  of  the  ash  comes  from  bone,  and  the  bony  frame- 
work is  from  6  to  9  per  cent  of  the  entire  bodies  of  domes- 
tic animals.  Williams  and  Emmett  found  that  the  total 
ash  in  the  bodies  of  pigs  forty  to  forty-three  weeks  old 
was  distributed  among  the  parts  as  follows:  about  four- 
fifths  in  skeleton,  one-ninth  in  the  boneless  meat  arid 
about  one-sixteenth  in  the  offal,  blood,  and  the  jowl  and 
intestinal  fats.  Of  the  water-soluble  ash,  only  about  one- 
twelfth  was  found  in  the  skeleton,  with  about  three-fifths 
in  the  boneless  meat.  This  distribution  of  the  ash  was  not 
the  same  in  pigs  forty  to  forty-three  weeks  of  age  as  for 
pigs  eighteen  weeks  of  age.  The  offal  and  carcasses  of 
the  younger  animals  contained  practically  twice  as  much 
as  those  of  the  older  pigs,  while  the  skeletons  contained 
only  about  three-fourths  as  much.  More  than  80  per 
cent  of  the  ash  of  bone  is  calcium  phosphate,  which  is 
associated  with  calcium  carbonate,  calcium  fluoride,  cal- 
cium chloride,  and  magnesium  phosphate. 

The  bones  of  all  species  of  animals  show  a  remarkable 
similarity  of  composition,  the  average  of  which  would  not 
be  far  from  the  following: 


46  THE  FEEDING   OF  ANIMALS 

TABLE  XVII.   IN  100  PARTS  OF  THE  ASH  OF  BONE  (AVERAGE) 

Calcium  phosphate 83.9 

Calcium  carbonate 13. 

Calcium  in  other  combinations .35 

Fluorine      23 

Chlorine .18 


97.66 

57.  Ash  elements  in  the  soft  tissues. — The  muscular 
tissue  and  other  soft  parts  of  the  animal  body  contain 
less  than  1  per  cent  of  incombustible  materials.  The  ash 
of  flesh  is  mostly  phosphoric  acid  and  potash,  accompanied 
by  comparatively  small  amounts  of  soda,  lime,  and  mag- 
nesia and  minute  quantities  of  chlorine  and  iron.   Unques- 
tionably, potassium  phosphate  is  the  predominating  salt 
in  flesh,  as  calcium  phosphate  is  in  bone. 

58.  Ash  elements  in  the  blood. — The  blood  contains 
a  variety  of  mineral  substances,  the  chief  of  which  is 
sodium  chloride,   or   common   salt,   although   a  minute 
amount  of  iron  is  present,  having  a  most  important  func- 
tion.   In  the  bile,  soda  is  abundant,  combined  mostly 
with  the  peculiar  organic  acids  of  this  secretion.  Chlorine 
is  a  constant  constituent  of  the  gastric  juice,  its  presence 
as  chlorhydric  acid   being   essential  to  digestion.    The 
preceding  are  some  of  the  prominent  facts  concerning 
the  inorganic  compounds  of  the  animal  body,  but  they 
are  only  a  brief  suggestion  of  the  knowledge  which  per- 
tains to  this  part  of  animal  chemistry. 


CHAPTER  V 

THE  COMPOUNDS  OF  ANIMAL  NUTRITION, 
CONTINUED— THE  NITROGEN  COMPOUNDS 

THE  nitrogen  compounds  of  the  vegetable  and  animal 
kingdoms  have  received  much  attention  from  scientific 
investigators  and  writers  during  the  past  fifty  years.  It 
has  been  generally  taught  that  certain  members  of  this 
class  of  substances  are  the  ones  most  important  in  the 
domain  of  animal  nutrition,  and  many  writers  have  given 
to  these  a  prominent  place  in  discussing  the  relative 
value  of  feeding-stuffs  and  have  almost  ignored  the  other 
nutrients.  It  is  now  conceded  that  relatively  the  func- 
tion and  value  of  protein  have  been  unduly  magnified. 
The  present  tendency  is  toward  a  fuller  discussion  of  the 
office  and  value  of  the  non-nitrogenous  bodies. 

59.  The  importance  of  protein. — There  can  scarcely 
be  any  disagreement,  however,  concerning  the  general 
proposition  that  the  proteins  play  a  leading  part  in  the 
processes  and  economy  of  animal  nutrition.  This  is  true 
for  several  reasons: 

(1)  The  nitrogen  compounds  are  those  fundamental 
to  the  energies  of  the  living  cells  which  make  up  the  tis- 
sues of  plants  and  animals.  The  basic  substance  of  the 
active  cell  is  protoplasm,  a  complex  nitrogenous  body, 
which  Huxley  called  "the  physical  basis  of  life."  Around 
this  primal  substance  seem  to  center  all  vital  activities, 
especially  the  transformation  of  the  raw  materials  of  the 
inorganic  world  into  the  organized  structures  of  life. 

(47) 


48  THE  FEEDING  OF  ANIMALS 

(2)  These  compounds  are  structurally  essential  to  the 
growth  of  animal  tissues  and  to  the  formation  of  milk. 
The  significance  of  this  fact  is  intensified  by  their  paucity 
in  many  of  the  feeding-stuffs  that  are  ordinarily  pro- 
duced on  the  farm. 

PROTEIN 

For  the  sake  of  brevity  and  convenience,  the  nitro- 
gen compounds  of  cattle  foods,  both  vegetable  and 
animal,  have  been  designated  as  a  class  by  the  single 
term  protein.  When,  therefore,  it  is  stated  that  a  feeding- 
stuff  contains  a  certain  percentage  of  protein,  reference 
is  made  to  the  total  mass  of  nitrogen  compounds  present, 
which  may  be  many  in  number  and  of  greatly  differing 
properties. 

60.  How  protein  is  determined. — The  proportion  of 
protein  (total  nitrogen  compounds)  in  a  feeding-stuff  as 
given  in  tables  of  feeding-stuff  analyses  is  ascertained  by 
determining  the  percentage  of  total  nitrogen  and  then 
multiplying  this  by  the  factor  6.25.  This  method  is  based 
on  the  assumption  that  the  average  percentage  of  nitro- 
gen in  protein  compounds  is  16,  which  is  not  true  to  so 
close  a  degree  of  approximation  as  was  formerly  believed 
to  be  the  case.  It  may  happen  in  some  instances  that  a 
determination  made  in  this  way  is  sufficiently  accurate, 
while  in  other  cases  the  margin  of  error  is  large.  Recent 
investigations  with  perfected  methods  show  percentages 
of  nitrogen  in  the  numerous  single  protein  substances 
found  in  the  grains  ranging  from  15.25  to  18.78.  These 
are  largest  in  certain  oil  seeds  and  lupines  and  smallest 
in  some  of  the  winter  grains.  Ritthausen,  a  prominent 
German  authority,  conceded  that  the  factor  6.25  should 
be  discarded,  and  suggests  the  use  of  5.7  for  the  larger 


THE  NITROGEN   COMPOUNDS  49 

number  of  cereal  grains  and  leguminous  seeds,  5.5  for 
the  oil  and  lupine  seeds,  and  6  for  barley,  maize,  buck- 
wheat, soja-bean,  and  white  bean  (Phaseolus),  rape  and 
other  brassicas.  Nothing  short  of  inability  to  secure 
greater  accuracy  justifies  the  longer  continuance  of  a 
method  of  calculation  which  is  apparently  so  greatly 
erroneous. 

61.  So-called  proteins  greatly  unlike. — As  previously 
stated,  protein  is  the  accepted  name  for  a  class  of  com- 
pounds.   Just  how  there  came  about  such  a  grouping 
of  a  large  number  of  substances  under  a  single  head  it  is 
not  necessary  to  consider  in  this  connection,  but  it  should 
be  made  clear  that  the  individual  compounds  which  are 
included   under  this  term   are  greatly  unlike  in  their 
chemical  and  physical  properties;  and  it  is  known  that 
they  differ  materially  in  their  nutritive  functions. 

62.  Classification  of  proteins. — It  is  very  evident  that 
it  is  not  only  convenient,  but  necessary,  to  classify  such 
a  heterogeneous  group  of  bodies  into  subdivisions  more 
nearly  alike  in  their  characteristics. 

The  most  recent  classification  is  one  recommended  by 
committees  representing  certain  scientific  bodies.*  Doubt- 
less this  classification  is  only  temporary  and  will  be 
modified  as  our  knowledge  of  the  compounds  of  nutrition 
is  enlarged.  The  grouping  now  agreed  upon  is  based  on 
chemical  constitution;  at  the  same  time  the  lines  of  cleav- 
age appear  to  have  reference  to  nutritive  function.  As  will 
be  noticed  later,  other  bodies  are  related  to  metabolism 
and  growth  which  it  is  not  now  possible  to  classify  as 
they  have  not  yet  been  isolated  and  their  chemical  con- 
stitution is  undetermined.  The  terms  used  in  this  classi- 
fication are  explained  in  the  text  which  follows: 

*Am.  Jour.  Phys.,  Vol.  XXI. 
D 


50 


THE  FEEDING  OF   ANIMALS 


Proteins 


Simple  . 


Conjugated 


Albumins 

Globulins 

Glutelins 

Alcohol  solubles 

Albuminoids 

Histones 

Protamines 

Nucleo-proteins 

Glyco-proteins 

Phospho-proteins 

Haemoglobins 

Lecitho-proteins 


Derived 


Primary 
derivatives 


Secondary 

derivatives 
f  Extractives 
Non-proteins<  Amides 
C 


/'Proteans 

<  Meta  proteins 
(Coagulated  proteins 

{Proteases 

<  Peptones 
(Peptides 


Certain  changes  in  terms  and  classifications  should  be 
noted.  The  term  proteid  is  abandoned,  and  the  term 
albuminoid  is  made  to  refer  to  the  bodies  formerly  classed 
as  collagens  or  gelatinoids.  The  newer  classification 
groups  the  proteins  on  the  basis  of  constitution  and  char- 
acteristic properties. 

Other  nitrogen  compounds  are  included  with  the  pro- 
teins by  the  present  methods  of  chemical  analysis,  such  as 
alkaloids  and  nitrates,  but  these  are  so  uncommon  in 
foods,  or  are  present  in  such  small  quantities,  that  they 
may  be  safely  ignored. 

63.  The  true  proteins. — The  proteins  are  the  main  and 
important  nitrogen  compounds  either  in  the  plant  or  in 
the  animal.  The  nitrogenous  bodies  of  seeds  are  little  else 
than  such  proteins,  while  young  plants,  and  especially 


THE  NITROGEN   COMPOUNDS 


51 


roots,  such  as  beets  and  turnips,  contain  more  nitrogen 
in  the  non-protein  form.  Proteins  are  the  chief  constit- 
uents of  muscular  tissue.  Their  chemical  constitution  is 
not  definitely  known,  but  it  is  generally  considered 
to  be  very  complex,  even  to  the  extent  of  several 
thousand  atoms.  These  bodies  are  constructed  from 
the  simpler  ones  of  the  inorganic  world  through  the 
vital  energies  of  plants,  and  in  order  to  serve  the 
purposes  of  nutrition  they  must  come  to  the  animal  fully 
organized. 

64.  Ultimate  composition  of  proteins. — The  ultimate 
composition  of  proteins,  that  is,  the  proportions  of  the 
elements  which  they  contain,  has  been  carefully  studied, 
and  while  there  are  material  differences  among  them  in 
this  respect,  the  limits  of  variation  are  not  especially 
wide,  as  can  be  seen  from  the  following  figures  according 
to  Osborne:* 

TABLE  XVIII.    COMPOSITION  OF  SOME  TYPICAL  PROTEINS 


Carbon 

Hydro- 
gen 

Nitro- 
gen 

Oxygen 

Sulfur 

Iron 

Phos- 
phorus 

Per  cent 

Percent 

Per  cent 

Per  cent 

Percent 

Per  cent 

Per  cent 

Egg-albumin      .    . 

52.75 

7.10 

15.51 

23.02 

1.616 

Lact-albumin     .    . 

52.19 

7.18 

15.77 

23.13 

1.73 

Leucosin     .... 

53.02 

6.84 

16.80 

22.06 

1.28 

Serum-globulin 

52.71 

7.01 

15.85 

23.32 

1.11 

Myosin  

52.82 

7.11 

16.67 

22.03 

1.27 

Edestin       .... 

51.50 

7.02 

18.69 

21.91 

.88 

Legumin     .... 

51.72 

6.95 

18.04 

22.90 

.385 

Casein     

53.13 

7.06 

15.78 

22.37 

.80 

.86 

Ovovitellin     .    .    . 

51.56 

7.12 

16.23 

23.24 

1.028 

.82 

Gliadin  

52.72 

6.86 

17.66 

21.73 

1.027 

Zein    

55.23 

7.26 

16.13 

20.78 

.60 

Oxyhemoglobin     . 

54.64 

7.09 

17.38 

20.16 

.39 

.335 

*  "Chemistry  of  Food  and  Nutrition,"  Sherman,  page  35. 


52  THE  FEEDING  OF  ANIMALS 

We  see  that  the  number  of  elements  ordinarily  found 
in  the  proteins  is  five,  nitrogen  and  sulfur  being  those  that 
chiefly  distinguish  these  bodies  from  all  others  which 
make  up  the  mass  of  combustible  matter.  Two  other 
elements  are  found  in  certain  of  these  bodies,  as,  for 
instance,  phosphorus  in  casein  and  ovovitellin  and  iron 
in  a  constituent  of  blood. 

65.  Familiar    examples    of    proteins. — Proteins    are 
familiar   objects,    and   their   properties   are   matters   of 
common  observation.    The  tenacious  cud  of  gum  from 
wheat  gluten,  the  strings  of  coagulated  albumin  which 
separate  from  the  cold-water  extract  of  fresh  lean  beef 
that  is  brought  to  the  boiling-point,  the  hardening  of  the 
white  of  an  egg  into  a  tough  mass  as  it  is  dropped  into 
boiling  water,  the  stiffening  of  the  muscular  tissue  of  the 
slaughtered  animal  or  the  rapid  formation  of  strings  of 
fibrin  in  the  cooling  blood — in  all  these  instances  there 
are  manifested  certain  chemical  or  physical  properties 
which  pertain  to  these  most  important  and  widely  uti- 
lized compounds. 

SIMPLE  PROTEINS 

66.  The  albumins. — The  albumins  have  several  sources. 
They  are  found  in  the  juice  of  plants,  in  certain  liquids 
of  the  animal  body  such  as  the  serous  fluids,  in  the  cell 
substance    of    muscular    tissue,    in    blood     and    milk, 
and     abundantly     in     eggs.      Unlike     other     proteins, 
these  compounds  are  freely  soluble  in  pure  cold  water, 
and    when   such   a   solution   is  heated   to  the  boiling- 
point,  they  separate  from  solution  by  coagulation  and 
become   insoluble    unless  acted    upon   by   some   strong 
reagent. 


THE  NITROGEN   COMPOUNDS  53 

When  macerated  beef  is  treated  with  cold  water  the 
albumin  in  it  goes  into  solution,  and  if  this  extract  is 
boiled  the  albumin  separates  in  clotted  masses. 

The  clear  serous  fluid  that  is  left  after  removing  the 
clot  from  blood  contains  albumin.  After  the  casein  is 
removed  from  milk  by  acid  or  rennet,  the  albumin  of  the 
milk  remains  in  the  whey.  It  is  this  which  in  part  causes 
milk  to  clot  if  brought  to  the  boiling-point.  As  stated,  one 
example  of  this  class  of  proteins  is  the  white  of  an  egg, 
which,  when  cooking  in  boiling  water,  becomes  a  hard, 
coagulated  mass.  Albumin  in  the  serous  fluids  and  in 
blood  is  called  serum-albumin;  in  milk,  lact-albumin,  and 
in  eggs,  ova-albumin. 

A  small  proportion  of  the  proteins  of  plants  is  found  to 
be  albumin;  for  instance,  Osborne  found  .3  to  .4  per  cent 
in  wheat,  .43  per  cent  in  rye,  .3  per  cent  in  barley,  .5  per 
cent  in  soja-beans,  and  some  in  most  seeds.  This  possesses 
essentially  the  same  characters  as  the  animal  albumin 
described  previously.  Whenever  a  vegetable  substance 
is  leached  with  water,  it  is  probably  this  protein  which 
would  be  the  first  to  suffer  removal  or  destructive 
fermentation. 

67.  The  globulins. — These  proteins  are  usually  asso- 
ciated with  albumins.  When  animal  tissues  are  treated 
with  water,  but  a  small  part  of  the  proteins  dissolve.  If, 
however,  we  add  to  the  water  a  mineral  salt,  especially 
common  salt  (sodium  chloride),  sufficient  to  secure  a 
10  per  cent  solution,  an  additional  and  considerable 
amount  of  protein  may  be  extracted.  Certain  compounds 
so  extracted  are  called  globulins,  and  differ  from  the 
albumins  in  being  practically  insoluble  in  pure  water  and 
in  a  saturated  solution  of  certain  mineral  salts,  such  as 
sodium  chloride.  The  so-called  globulins  form  an  impor- 


54  THE   FEEDING   OF   ANIMALS 

tant  part  of  the  protein-content  of  plants  and  of  animal 
tissues,  both  in  quantity  and  in  having  a  maximum 
nutritive  usefulness. 

68.  Plant  globulins. — In  plants  these  proteins  seem 
to  be  especially  abundant  and  widespread.  Our  most 
recent  and  most  reliable  knowledge  of  plant  proteins 
comes  from  investigations  by  Osborne.  In  these  researches 
the  seeds  of  many  species  of  agricultural  plants  were 
studied,  all  of  which  were  found  to  contain  globulins. 
In  some  the  proteins  consisted  largely  of  these  com- 
pounds. The  percentage  content  in  certain  seeds  was 
determined  approximately : 

TABLE  XIX.    GLOBULINS  IN  CERTAIN  SEEDS 


Kidney  bean  .  .  .  . 

Per  cent 
20. 

Lentil    .    .    . 

Per  cent 
.    .    .    .       13. 

Cottonseed  meal  .  . 
Peas  

15.8 
10. 

Horse  bean  . 
Maize    .    .    . 

.    .    .    .       17. 
.    .    .    .           .4 

Lupin  
Wheat  . 

26.2 
.6 

Soybean    .    . 

.  chiefly  globulin 

The  seeds  of  the  legumes,  as  a  rule,  contain  the  larg- 
est proportion  of  these  proteins,  the  cereal  grains 
having  only  a  very  small  part  of  their  protein  in  this 
form. 

From  present  knowledge,  many  seeds  appear  to  have 
characteristic  globulins  which  differ  among  themselves 
in  their  chemical  properties.  These  have  been  given 
names  derived  from  the  general  names  of  the  species  in 
which  they  are  found.  Thus  we  have  amandin  in  almonds, 
avenalin  in  oats,  corylin  in  walnuts,  excelsin  from  the 
Brazil-nut,  phaseolin  in  several  species  of  beans,  glycin 
in  the  soybean,  maysin  in  maize,  vicilin  in  horse  beans, 
lentils,  and  peas,  vignin  in  the  cowpea,  and  tuberin  in 
the  potato.  One  globulin  called  edestin  appears  to  be 


THE  NITROGEN   COMPOUNDS  55 

quite  generally  distributed  in  the  seeds  of  agricultural 
plants,  having  been  found  in  a  larger  number  than 
any  other  protein  yet  discovered,  including  all  the 
cereals,  castor  bean,  cottonseed,  flaxseed,  hemp,  squash, 
and  sunflower,  although  it  is  not  abundant  in  any  of 
these. 

69.  Animal  globulins. — The  animal  globulins  exist 
abundantly  in  muscle  and  blood.  If  finely  divided,  well- 
washed  muscle  (lean  meat)  is  treated  with  a  10  per 
cent  salt  solution,  first  by  rubbing  it  in  a  mortar  with 
fine  salt,  and  then  adding  enough  water  to  secure  the 
proper  strength  of  solution,  a  globulin  is  dissolved  which  is 
derived  from  a  muscle  protein  designated  by  some  authors 
as  myosin.  It  is  believed  that  myosin  coagulates  in  the 
muscle  upon  the  death  of  an  animal  forming  a  clot  some- 
times called  myosin-fibrin.  The  theory  has  been  proposed 
that  myosin  acts  as  a  "mother"  substance  in  the  muscle 
from  which  myosin-fibrin  is  formed  in  much  the  same 
way  as  fibrin  is  developed  in  clotting  blood  from  a  pre- 
existing body,  but  no  single  view  as  to  exactly  what 
occurs  is  fully  accepted.  Other  terminology  has  been 
proposed,  viz.,  that  the  mother  substance  shall  be  named 
myosinogen  to  correspond  to  fibrinogen,  myosin  being  the 
coagulation  product.  Much  confusion  and  indefiniteness 
exist  with  reference  to  the  chemistry  of  muscle  proteins. 
There  is,  nevertheless,  a  general  agreement  that  rigor 
mortis  is  due  to  a  clotting  of  the  muscle,  accompanied  by 
marked  chemical  transformations.  It  is  held  that  fer- 
ments are  present  in  the  muscle,  to  the  influence  of  which 
these  changes  are  due,  and  without  which  they  do  not 
occur. 

Another  prominent  globulin  is  the  fibrinogen  found  in 
the  blood.  When  blood  is  drawn  from  the  veins  and  cools, 


56  THE  FEEDING  OF  ANIMALS 

it  clots,  which  is  nothing  more  than  the  formation  of 
strings  of  fibrin,  perhaps  through  the  influence  of  a  fer- 
ment, which  has  been  named  thrombin.  Fibrin  as  such  is 
not  found  in  living  blood.  A  remarkable  fact  is  that  so 
long  as  the  blood  is  retained  in  the  arteries  and  veins, 
even  if  the  animal  dies  and  grows  cold,  this  clotting  does 
not  appear. 

Serum-globulin  is  a  collective  name  for  several  globu- 
lins, which  exist  in  blood-serum  and  in  the  other  fluids  of 
the  animal  body,  such  as  lymph  and  its  allies,  including 
those  exudations  which  pertain  to  diseased  conditions, 
especially  dropsical. 

One  more  protein  has  been  generally  classified  as  a 
globulin,  although  differing  in  some  respects  from  the 
other  members  of  this  class,  and  more  recently  is  classed 
as  a  phospho-protein.  Reference  is  made  to  vitellin, 
which  is  the  principal  protein  in  the  yolk  of  eggs.  It  is 
there  intimately  mixed  with  certain  peculiar  phosphorized 
bodies,  which  we  shall  notice  later. 

70.  Glutenins. — These  form  a  large  part  of  nitrogen 
compounds  of  the  cereal  grains  and  possibly  of  other 
seeds.   They  are  insoluble  in  water,  alcohol,  and  neutral 
salt  solutions,  but  readily  dissolve  in  very  dilute  acids 
and   alkalies.     The   glutenin   of    wheat,   found    in   the 
tenacious  substance  that  is  left  after  washing  the  starch 
out  of  wheat  flour,  is  the  best-known  protein  of   this 
class  and  is  an  important  constituent  of  wheat  flour, 
existing  there  on  the  average  to  over  40  per  cent  of  the 
total  protein. 

71.  Alcohol-soluble    proteins.* — Alcohol-soluble    pro- 
teins have  been  found  in  all  the  cereal  grains  so  far  exam- 

*  Osborne  and  others  propose  the  name  prolamins.  Science,  Vol. 
XXVI,  pages  417-427. 


THE  NITROGEN   COMPOUNDS  57 

ined.  The  principal  ones  to  be  mentioned  are  gliadin 
from  wheat,  zein  from  corn,  and  hordein  from  barley. 
Gliadin  is  more  abundant  in  the  wheat  kernel  than  is  the 
glutenin  with  which  it  is  associated,  the  two  together 
constituting  over  80  per  cent  of  the  total  proteins  of  that 
cereal.  The  proportion  of  gliadin  in  wheat  flour  has  much 
to  do  with  its  quality  for  bread-making  purposes.  It  ap- 
pears that  the  best  bread  flour  contains  about  twice  as 
much  gliadin  as  glutenin. 

72.  Albuminoids. — This  term,  according  to  the  classi- 
fication still  in  more  or  less  use  in  the  United  States,  has 
been  understood  as  including  various  proteins  such  as 
the  albumins,  and  globulins.  The  classification  now 
recommended  confines  the  term  to  proteins  found  chiefly 
in  the  animal  body  in  such  parts  as  the  cartilages,  bones, 
feathers,  hair,  hoofs,  horns,  and  nails.  These  proteins 
are  also  obtained  from  the  threads  of  silkworms  and  from 
sponges.  The  albuminoids  have  group  names,  such  as 
collagen  in  cartilage  and  bone,  keratins  in  feathers,  hair, 
hoofs,  horns,  nails,  and  similar  exterior  tissues,  fibroin 
in  the  threads  of  silkworms,  and  spongin  in  the  frame- 
work of  sponges. 

Gelatine,  so  well  known  to  the  housewife,  is  derived 
from  collagen.  When  meat  containing  tendons  (cartilage) 
is  submitted  to  the  action  of  boiling  water,  there  is 
obtained  in  the  extract  a  gelatinous  substance  which 
becomes  evident  when  the  extract  is  cooled.  This  gela- 
tine is  insoluble  in  cold  water,  but  dissolves  in  hot.  As  a 
dry  commercial  article,  it  is  a  tenacious  substance  which, 
when  prepared  in  thin  layers,  is  transparent.  When  col- 
lagen and  gelatine  are  acted  upon  by  tannic  acid,  as,  for 
instance,  when  the  skin  of  an  animal  is  treated  with  an 
extract  from  hemlock  or  oak  bark,  the  result  is  a  sub- 


58  THE  FEEDING  OF  ANIMALS 

stance  which  does  not  putrefy  and  which  gives  to  the 
tanned  hide  the  properties  of  leather.  Gelatine  is  much 
used  in  various  food  preparations. 

It  is  characteristic  of  the  keratins  such  as  hair  and  horn 
that  they  contain  a  relatively  large  proportion  of  sulfur, 
the  analysis  of  horn  and  hair  showing  as  high  as  5  per 
cent,  the  average  amount  in  horn  being  3.3  per  cent.  The 
keratin  bodies  serve  to  give  rigidity  and  wearing  quali- 
ties to  certain  exterior  animal  tissues. 

73.  Histories,    protamines. — The    proteins    in    these 
two  groups  do  not  occur  as  such  in  nature,  and  are  ob- 
tained only  by  separating  them  from  some  combination. 
The  two  groups  are  alike  in  being  basic  in  character 
and    in    being    found    in    the    spermatozoa    of    fishes. 
Histones  have  also  been  obtained  from  the  blood  cor- 
puscles of  a  goose  and  from  the  white  blood  corpuscles 
of  thymus  glands. 

CONJUGATED   PROTEINS 

74.  Nucleo-proteins. — These  are  complex,  phosphorus- 
bearing    proteins    that    sustain    an    important    nutri- 
tive function.    They  are  regarded  as  a  combination  of 
nuclein  with  an  albumin,  the  nucleins  being  compounds 
of  nucleic  acid  and  albumin,  and  nucleic  acid  yielding  on 
cleavage  phosphoric  acid,  certain  nitrogenous  bases  known 
as  purins,  and  a  carbohydrate. 

The  nucleo-proteins  are  associated  with  the  nuclei  of 
the  cells  that  make  up  both  plant  and  animal  tissues. 
They  are  relatively  abundant  in  glandular  tissues  such  as 
the  spleen,  pancreas,  thymus  gland,  and  liver.  The 
spermatozoa  masses  of  fishes  are  especially  rich  in  these 
compounds.  Because  certain  bases  known  as  purins 


THE  NITROGEN   COMPOUNDS  59 

which  arise  from  the  cleavage  of  nucleo-proteins  are 
regarded  as  the  progenitors  of  uric  acid,  persons  with 
uric-acid  tendency  have  been  advised  to  avoid  eating 
certain  animal  foods  such  as  beef  and  liver,  or  any  others 
known  to  contain  these  compounds  abundantly.  Experi- 
ments show  that  the  feeding  of  certain  tissues  rich  in 
nucleo-proteins  increases  the  output  of  uric  acid,  while 
adding  to  the  diet  a  large  amount  of  purin-free  proteins 
such  as  albumin  does  not  have  this  effect. 

75.  Glyco-proteins. — These  are  bodies  that  upon  cleav- 
age are  decomposed  into  a  protein  and  a  carbohydrate. 
The  best-known  glyco-proteins  are  the  mucins  that  are 
secreted  by  the  mucous  membranes  of  the  air  passages 
and  of  the  alimentary  canal  and  by  certain  glands  such  as 
the  salivary.   Certain  of  these  compounds  contain  phos- 
phorus and  others  do  not. 

76.  Phospho-proteins. — Like      the      nucleo-proteins, 
these  compounds  contain  phosphorus,  Jbut  on  cleavage 
do  not  yield  the  purin  bases.   The  best-known  phospho- 
protein  is  the  casein  of  milk,  a  compound  exceedingly 
important    in    human    nutrition,    especially    with    the 
young. 

This  compound  is  a  secretion  of  the  mammary  gland 
of  many  species  of  animals,  and  doubtless  originates  in 
the  gland  cells.  The  casein  from  different  species  of 
mammals  differs  somewhat  in  chemical  and  physical 
properties.  Casein  is  insoluble  in  water,  but  exists  in 
milk  in  suspension.  It  is  not  coagulated  by  heat  but 
curdles  when  a  weak  acid  is  added  to  milk,  as,  for  instance, 
vinegar.  The  same  result  is  produced  by  a  generous  quan- 
tity of  common  salt.  When  milk  is  received  into  the 
human  stomach,  the  casein  coagulates  (the  milk  curdles) 
through  the  action  of  a  ferment  in  the  gastric  juice  and 


60  THE  FEEDING  OF  ANIMALS 

this  coagulation  is  mechanically  unlike,  at  least,  with 
milk  from  different  species.  The  action  of  this  ferment 
on  casein  is  utilized  in  cheese-making  in  the  development 
of  a  curd  which,  with  its  inclosed  fat,  is  separated 
from  the  whey  and  pressed  into  compact  masses  and 
later  allowed  to  undergo  certain  changes  due  to  other 
ferments. 

Other  phospho-proteins  exist,  one  being  the  vitellin 
in  the  yolk  of  eggs  which,  as  prepared,  contains 
lecithin. 

77.  Haemoglobin. — Blood   contains   a   peculiar   com- 
pound  known   as   haemoglobin.    When  decomposed,   it 
separates  into  a  protein,  globin,  and  a  coloring  matter 
haemochromogen,  which,  when  charged  with  oxygen,  is 
called  hsematin.   This  oxidation  changes  the  haemoglobin 
to  oxy-haemoglobin.    This  haemoglobin  in  the  blood  of 
mammals  contains,  besides  carbon,  nitrogen,  oxygen,  and 
hydrogen,  sulfur  and  iron.   The  latter  varies  in  per  cent 
from  .34  to  .48,  and  sustains  an  essential  relation  to  the 
functions   of  the  blood.     The   blood   pigment  has  the 
property  of  taking  up  and  releasing  oxygen  with  great 
readiness,  carrying  its  load  of  oxygen  out  of  the  lungs, 
giving  it  up  to  oxidation  processes  in  various  parts  of  the 
body,  and  bringing  to  the  lungs  in  its  place  the  result- 
ing carbon  dioxid  to  be  discharged  into  the  air.    The 
blood  changes  color  with  the  acquisition  and  loss  of  the 
oxygen. 

78.  Lecitho-proteins. — From   the   yolk   of   eggs,   the 
mucous  membranes,  and  the  kidneys,  and  doubtless  from 
other  sources,  are  obtained  a  conjugated  protein  con- 
taining lecithin.    The  constitution  and  special  function 
of  this  body  are  not  well  understood. 


THE  NITROGEN  COMPOUNDS  61 

DERIVED   PROTEINS 

These  are  divided  into  primary  and  secondary  protein 
derivatives.  Primary  protein  derivatives  are  those  that 
have  been  slightly  modified  by  the  action  of  water,  very 
dilute  acids,  or  enzyms,  or  are  the  result  of  the  action  of 
acids  and  alkalies  whereby  products  soluble  in  weak 
acids  and  alkalies  are  formed.  Coagulated  proteins 
resulting  from  the  action  of  heat  and  alcohol  are  classed 
in  this  division. 

Secondary  protein  derivatives  are  those  in  which  the 
modifying  changes  (hydrolytic,  or  the  taking  up  of  water) 
through  the  action  of  acids  or  enzyms,  have  proceeded 
beyond  the  incipient  stage  with  the  formation  of  bodies 
that  are  soluble  in  water.  In  this  division,  the  most 
important  compounds  are  the  proteoses  and  the  peptones, 
the  latter  having  suffered  a  greater  change  by  hydrolysis 
than  the  former. 


1.   PRIMARY  PROTEIN  DERIVATIVES 

79.  Proteans  and  metaproteins. — When  proteins  are 
acted  on  by  acids  or  alkalies,  they  are  modified  in 
proportion  to  the  strength  of  the  reacting  acid  or  alkali 
and  the  length  of  time  that  the  action  continues.  With 
acid  or  alkalies  of  sufficient  strength,  there  are  formed 
products  soluble  in  weak  acids  and  alkalies  (meta-pro- 
teins). 

80.  Coagulated  proteins. — There  are  several  agents 
which  convert  albumins  and  other  proteins  into  a  coagu- 
lated mass,  such  as  a  boiling  heat,  alcohol,  and  certain 
neutral  salts  and  the  action  of  an  enzym.  For  instance, 


62  THE  FEEDING  OF  ANIMALS 

with  albumin  from  flesh  or  the  white  of  an  egg,  boiling 
water  converts  it  into  a  coagulum  that  is  insoluble  in 
water  and  is  rendered  soluble  only  by  such  agents  as 
acids  and  alkalies  upon  heating. 

Dropping  a  soluble  protein  into  alcohol  has  the  same 
effect.  Globulins  are,  as  a  rule,  affected  in  the  same  way. 
The  nature  of  this  modification  is  not  known. 


2.   SECONDARY  PROTEIN  DERIVATIVES 

81.  Proteoses,  peptones. — When  various  proteins  such 
as  albumin  or  globulin  are  subjected  to  the  action  of  a 
weak  acid  or  of  certain  enzyms,  they  undergo  what  is 
known  as  hydrolysis.  This  change  involves  a  cleavage 
(splitting)  of  the  protein  body  accompanied  by  the  taking 
up  of  the  elements  of  water.  In  this  way  are  formed  pro- 
teoses  and  peptones,  the  latter  being  proteins  that  are 
soluble  in  water.  A  proteose  is  an  intermediate  stage 
between  the  original  protein  and  a  peptone,  and  it  receives 
a  name  according  to  its  source,  as  albumose,  globulose, 
and  caseose,  according  as  an  albumin,  a  globulin,  or  casein 
is  its  source. 

Peptone  was  formerly  regarded  as  the  final  product  of 
enzym  action  in  digestion,  but  we  now  know  that  the 
digestion  of  the  proteins  proceeds  much  farther.  These 
hydrolyzed  bodies  are  found  abundantly  in  the  digestive 
tract  during  digestion,  the  proteoses  as  stated  being  an 
intermediate  stage  of  digestion  between  the  original  pro- 
teins and  the  peptones.  This  means  that  the  formation 
of  the  final  products  of  protein  digestion  is  a  progressive 
step.  Proteoses  and  peptones  may  also  be  obtained  by 
laboratory  methods.  It  should  be  noted  that  commercial 
peptones  are  largely  proteoses. 


THE  NITROGEN   COMPOUNDS  63 

82.  Important  properties  of  the  proteins. — The  pre- 
vious description  of  the  various  groups  of  proteins  cannot 
be  understood  to  its  fullest  extent  except  by  those  who 
have  a  good  knowledge  of  the  fundamentals  of  organic 
chemistry.   Nevertheless,  the  facts  given  serve  to  impress 
the  important  chemical  and  physical  properties  which 
these  bodies  possess,  and  point  to  the  necessity  of  study- 
ing them  individually  in  their  relation  to  foods  and  nutri- 
tion. It  is  not  rational  to  speak  of  protein  as  if  the 
term  represents  an  individual  entity,  but  the  members 
of  this  general  class  of  compounds  must  be  considered 
by  sub-classes    at    least,    in   discussing  their   place  in 
nutrition. 

A  fact  of  importance  is  the  varying  constitution  of 
the  protein  molecule,  and  consequently  the  possible 
variation  in  the  nutritive  function  of  the  individual 
proteins. 

83.  The  unlike  constitution  of  the  various  proteins. — 
We  have  already  seen  that  certain  proteins  are  particu- 
larized in  part  by  containing  phosphorus,  others  sulfur, 
and  others  iron.  A  phosphorus-bearing  protein  may  have, 
and  undoubtedly  does  have,  a  nutritive  function  that 
cannot    be    exercised    by    an    albumin    not    carrying 
phosphorus. 

84.  Cleavage   products  of  the  proteins. — It  is  well 
known  that  when  proteins  are  submitted  to  the  action 
of  acids,  alkalies,  and  certain  ferments   (enzyms)  they 
break  up  into  simpler  compounds  which  we  speak  of  as 
cleavage  products,  chiefly  amino-acids  which  are  some- 
times designated  as  the  building-stones  of  the  proteins. 
It  is  very  significant  that  the  kinds,  and  especially  the 
proportions,  of  these  products  differ  greatly  with  different 
proteins.    For  instance,  the  purin  bases,  which  certainly 


64 


THE  FEEDING  OF  ANIMALS 


sustain  important  physiological  relations,  are  present 
in  beef  and  certain  glands  used  as  food,  but  absent  in 
milk  and  eggs.  The  variations  in  the  decomposition  prod- 
ucts of  certain  vegetable  proteins  are  striking,  as  also 
are  the  differences  in  this  respect  between  vegetable  and 
animal  proteins,  and  these  differences  have  an  important 
bearing  on  the  value  of  the  inividual  proteins  for  the 
purposes  of  growth.  The  following  table  taken  from 
Hammarsten's  "Text-book  of  Physiological  Chemistry," 
seventh  edition,  is  worthy  of  attention : 


TABLE  XX.    CLEAVAGE  PRODUCTS  OP  THE  PROTEINS 
Plant  Proteins 


Edestin 

Legumin 

Hordein 

Gliadin 

Zein 

Glycocoll     .    . 

3.8 

.38 

.68 

Alanine    

3.6 

2.08 

.43 

2. 

9.79 

Valine      
Leucine    

5.6 
20.9 

1. 

8. 

.13 
5.67 

3.34 
6.62 

1.88 
19.55 

Serine  ^  v  '  .' 

.33 

.53 

.13 

1.02 

Aspartic  acid 
Glutamic  acid     .    . 
Cystine 

4.5 
18.74 
.25 

5.3 

13.8 

43.19 

.58 
43.66 
.45 

1.71 
26.17 

Phenylalanine     .    »   .  * 

Tyrosine      .    .    .  >.v  . 

2.4 
2.1 

3.75 
1.55 

5.03 
1.67 

2.35 
1.2 

6.55 
3.55-10.1 

Proline                     . 

1.7 

322 

1373 

13.22 

9.04 

Oxyproline      ...'>. 
Tryptophane       . 
Histidine      ... 

2. 
.38 
1.1 

2.42 

1.28 

1. 

.61 

'.82 

Arginine       .    .    .    .  -  -»" 
Lysine  .   . 

11.7 
1. 

10.12 
4.29 

2.16 

3.16 

1.55 

Ammonia     

1.49 

4.87 

5.22 

3.61 

THE  NITROGEN  COMPOUNDS 

Animal  Proteins 


65 


Lact-al- 
bumin 

Ser-al- 
bumin 

Ova-al- 
bumin 

Ser-glo- 
bulins 

Fibrin 

Casein 

Viteffin 

Glycocoll  .  .  .  . 

Alanine  .  .  .  . 
Valine  
Leucine  .... 
Isoleucine 

2.5 
.9 
19.4 

2.7 
20.' 

2.2 
2.5 
10.7 

3.5 

2.2 

18.7 

3. 
3.6 
1. 
15. 

1.5 
7.2 
9.35 
1  43 

1.1 

.75 

2.4 
11. 

Serine  

.6 

.8 

.5 

Aspartic  acid  .  . 
Glutamic  acid  .  -. 
Cystine  ..... 
Phenylalanine  .  . 
Tyrosine  .  .  .';. 
Proline  .  .  .  •  .  .  ^ 

1. 
10.1 

2.4 
.85 
4. 

3.1 
7.7 
2.5 
3.1 
2.1 
1.04 

2.2 
9.1 
.3 
5.17 
1.77 
3.56 

2.5 
8.5 
1.51 
3.8 
2.5 
2.8 

2. 
10.4 
1.17 
2.5 
3.5 
3.6 

1.39 
15.55 
.07 
3.2 
4.5 
6.7 
.23 

2.13 

12.95 

2.8 
3.37 
4.18 

Tryptophane 

307 

1.5 

Histidine  .... 
Arginine  ....  . 
Lysine  ....  ... 
Ammonia  .... 

1.71 

4.91 
3.76 
1.34 

•   f 

3. 

4. 

2.5 
3.81 
5.95 
1.6 

1.9 
7.46 
4.81 
1.25 

In  view  of  later  discussions  it  is  well  to  note  in  this 
connection  certain  marked  differences  in  the  kind  and  pro- 
portions of  the  cleavage  products  (building-stones)  of  the 
individual  proteins. 

For  example,  glutamic  acid  is  found  in  the  plant 
proteins  in  much  larger  proportion  than  in  animal  pro- 
teins; lysine  is  absent  from  the  alcohol-soluble  proteins 
hordein,  gliadin,  and  zein,  and  proline  is  found  in  much 
larger  proportion  in  these  than  in  any  others.  It  is  safe  to 
conclude  that  certain  plant  proteins  cannot  be  rebuilt 
into  an  equal  quantity  of  animal  proteins. 

It  should  be  noted,  however,  that  a  comparison  of 
vegetable  and  animal  proteins  shows  in  general  a  close 
resemblance  in  the  kind  of  building-stones  out  of  which 

E 


66  THE  FEEDING  OF  ANIMALS 

they    are    constructed,    although    the    proportions    are 
unlike. 

NITROGEN   COMPOUNDS  THAT  ARE  NON-PROTEINS 

In  the  usual  method  for  determining  the  proteins  of  a 
food  by  multiplying  the  total  nitrogen  present  by  a  fac- 
tor, there  is  included  in  the  calculation  nitrogen  that  does 
not  come  from  true  proteins,  but  from  compounds  that 
possess  physical  and  chemical  properties  greatly  removed 
from  those  which  characterize  albumin  and  other  true 
proteins.  Their  office  as  nutrients  is  probably  less  com- 
prehensive than  that  of  the  proteins. 

85.  Amino-acids  and  amides. — These  compounds  re- 
sult from  the  union  of  organic  acids  and  the  group  NH2. 
Whether  the  resulting  compound  is  an  amino-acid  or  an 
amide  depends  upon  the  manner  of  combination.  Cer- 
tain of  the  amino-acids  may  be  produced  in  the  labora- 
tory by  synthesis,  but  in  the  main  they  are  obtained 
from  the  cleavage  of  protein  through  the  action  of  acids 
or  alkalies  or  ferments  (enzyms).  They  are  found  abun- 
dantly in  the  alimentary  canal  during  the  digestion  of  food 
as  a  result  of  the  action  of  the  digestive  enzyms  on  pro- 
teins. Amides  occur  in  plants.  Asparagine  is  an  amide  of 
amino-succinic  acid,  first  found  in  young  asparagus  shoots, 
and  glutamine  is  an  amide  of  amino-glutaric  acid,  found  in 
germinating  pumpkin  seeds.  They  are  soluble  in  water,  and 
consequently  are  diffusible  throughout  the  plant  tissues. 
It  is  believed  that  such  amides  are  forms  in  which  the 
nitrogen  compounds  of  the  plant  are  transferred  from  one 
part  to  another,  as,  for  instance,  from  the  stem  to  the  seed. 
It  has  generally  been  held  that  these  bodies  are  more  abun- 
dant in  young  plants  than  in  mature.  A  larger  part  of  the 
nitrogen  of  roots  and  tubers  is  found  in  these  compounds 


THE  NITROGEN   COMPOUNDS  67 

than  in  other  foods,  the  proportion  in  grains  being  the 
least,  and  is  very  small  indeed.  Such  investigations  as 
have  been  conducted  point  to  the  conclusion  that  amides 
do  not  function  wholly  as  do  the  proteins.  This  is  one 
reason  for  regarding  the  protein  of  certain  vegetable  foods 
as  of  less  value  than  that  of  the  grains  and  grain  products. 
86.  Extractives. — These  are  bodies  found  in  the  extract 
obtained  from  beef  with  cold  water.  After  the  albumin 
has  been  removed  from  such  an  extract  by  boiling,  these 
compounds  known  as  creatin  and  creatinin  chiefly  con- 
stitute the  nitrogenous  solids  that  remain.  Their  food 
value  is  small,  for  they  appear  to  be  largely  eliminated 
from  the  body  in  the  urine  without  change. 


CHAPTER  VI 

THE  COMPOUNDS  OF  ANIMAL  NUTRITION, 

CONCLUDED— CARBOHYDRATES,  ACIDS, 

FATS,  AND  OILS 

MUCH  the  larger  proportion  of  the  dry  matter  of  cattle 
foods  consists  of  non-nitrogenous  material.  While  these 
nitrogen-free  compounds  have  not  been  regarded  as 
fundamentally  so  important  as  are  the  proteins,  in  quan- 
tity they  unquestionably  occupy  the  first  rank.  The 
activities  of  plant  life  are  largely  devoted  to  their  pro- 
duction, and  their  use  by  animal  life  is  correspondingly 
extensive.  They  may  properly  be  called  the  main  fuel- 
supply  of  the  animal  world.  Other  nutrients  aid  in  main- 
taining muscular  activity,  to  be  sure,  but  these  compounds 
are  the  principal  storehouse  of  that  sun-derived  energy 
which  furnishes  the  motive  power  exhibited  in  all  animal 
life.  They  also  fill  a  necessary  office  in  the  formation  of 
milk  and  in  the  fattening  of  animals.  This  class  of  com- 
pounds greatly  predominates  in  the  usual  farm  crops, 
even  in  those  of  the  legume  family. 

87.  Elementary  composition  of  the  non-nitrogenous 
compounds. — The  non-nitrogenous  compounds  contain 
only  three  elements — carbon,  hydrogen,  and  oxygen. 
They  may  be  derived,  therefore,  wholly  from  air  and 
water,  and  they  constitute  that  portion  of  foods  which  is 
drawn  from  never-failing  and  costless  sources  of  supply. 
The  elementary  composition  of  typical  nitrogen-free 
bodies  is  given  in  this  connection: 

(68) 


CARBOHYDRATES,   ACIDS,   FATS,  OILS 


69 


TABLE  XXI 


Cellu- 
lose 

Starch 

Glucose 

Saccha- 
rose 

Stearin 

Olein 

Carbon  
Hydrogen  

Percent 
44.4 

6.2 
49.4 

Percent 
44.4 

6.2 
49.4 

Percent 
40. 

6.7 
53.3 

Percent 

42.1 
6.4 
51.5 

Percent 
76.7 
12.4 
11. 

Per  cent 

77.4 
11.8 
10.8 

Oxygen  

88.  Classification   of   non-nitrogenous   compounds. — 
The  non-nitrogenous   compounds   of  foods  are   usually 
divided  into  two  main  classes,  viz.,  carbohydrates  and 
similar  bodies  and  fats  and  oils.    The  first  class  often 
bears  the  name  nitrogen-free  extract,  but  the  carbohy- 
drates are  its  principal  members.    Crude  fiber  belongs  in 
this  class.  The  second  is  known  by  the  chemist  as  ether- 
extract,  because  ether  is  used  to  extract  the  fats  or  oils 
from  the  vegetable  substances  in  which  they  are  con- 
tained.  The  actual  fat  obtained  from  vegetable  foods  is 
always  less,  however,  than  the  ether-extract,  because  the 
ether  takes  into  solution  other  compounds  than  the  fats. 
It  should  be  noted  that  the  last  two  compounds  of  the 
above  table,  which  are  fats,  are  relatively  richer  in  car- 
bon and  hydrogen  and  poorer  in  oxygen  than  the  other 
compounds  mentioned,  which  are  carbohydrates.    This 
fact  has  an  important  relation  to  nutritive  value. 

89.  The  carbohydrates. — In  order  to  understand  the 
carbohydrates   as   individual   compounds   and   in   their 
relations  to  each  other  and  to  the  processes  of  nutrition, 
it  is  necessary  to  consider  them,  in  general  outlines  at 
least,  from  the  standpoint  of  the  chemist. 

The  term  carbohydrates,  as  it  is  used,  like  the  term 
protein,  is  collective  and  includes  a  great  variety  of  com- 
pounds. By  their  common  names  we  know  them  as  sugars, 


70  THE  FEEDING  OF  ANIMALS 

starches,  celluloses,  gums,  and  so  on.  Chemically  we  dis- 
tinguish them  by  their  structure  and  by  their  relation 
to  one  another. 

90.  Classification  of  carbohydrates  according  to  struc- 
ture.— The  structure  of  certain  sugars  is  such  that  their 
molecules  cannot  be  divided  into  simpler  compounds  that 
retain  the  carbohydrate  character,  and  these  are  known 
as  mono-saccharides.  To  this  class  belong  glucose  (grape- 
sugar)  and  fructose  (fruit-sugar).    On  the  other  hand, 
there  are  a  large  number  of  carbohydrates,  one  molecule 
of  which  by  treatment  in  certain  ways  may  be  converted 
into  two  or  more  molecules  of  a  mono-  (simple)  sugar. 
For  instance,  one  molecule  of  starch,  when  submitted  to 
the  action  of  an  acid  or  of  certain  ferments,  breaks  up 
into  several  molecules  of  glucose,  and  so  starch  is  known 
as  a  poly-saccharide.    Other  poly-saccharides  are  sucrose 
(cane-sugar),  maltose  (malt-sugar),  lactose  (milk-sugar), 
cellulose,  and  the  gums,  all  of  which  may  be  split  up  into 
mono-  or  simple  sugars.    The  poly-saccharides  are  sub- 
divided into  di,  tri,  and  so  on,  according  as  they  break  up 
into  two,  three,  or  more  molecules  of  a  simple  sugar. 

There  are  subdivisions  of  the  mono-sugars  also,  on 
the  basis  of  carbon  atoms  in  their  molecules  and  thus  we 
have  the  names  diose,  triose,  tetrose,  pentose,  hexose, 
heptose  for  sugars  having  two,  three,  four,  five,  six,  or 
seven  carbon  atoms  in  the  molecule.  It  may  be  remarked 
here  that  it  is  among  the  hexose  (six-carbon)  sugars  or  their 
multiples  that  we  find  the  carbohydrates  most  important 
to  human  nutrition. 

91.  The   mono-saccharides   or   simple    sugars. — The 
simple  sugars  that  are  most  important  in  animal  nutri- 
tion are  dextrose    (grape-sugar),   levulose    (fruit-sugar), 
and  galactose  (from  milk-sugar).    These  are  hexose  (six- 


CARBOHYDRATES,   ACIDS,   FATS,   OILS  71 

carbon)  sugars.  The  pentoses  are  also  simple  sugars,  but, 
as  we  shall  see,  they  scarcely  occur  in  nature,  being 
obtained  chiefly  by  splitting  up  certain  gums. 

92.  Dextrose. — An  important  simple  sugar  is  dextrose 
or  grape-sugar,  or  what  is  known  in  the  market  as  glu- 
cose.  Except  in  the  hands  of  the  chemist  it  is  seldom 
seen  as  crystals,  although  these  appear  in  the  "candying" 
of  honey  and  raisins.   It  is  a  constituent  of  molasses  and 
the  sirups.    Dextrose  is  found  in  practically  the  same 
plants  that  contain  saccharose,  such  as  sorghum,  maize, 
and  the  fruits.    So  far  as  known,  it  is  always  associated 
with  some  other  sugar.  On  account  of  its  difficult  crystal- 
lization and  a  lower  degree  of  sweetness,  it  is  less  valuable 
for  commercial  purposes  than  cane-sugar.    That  which 
appears  in  the  market  is  largely  made  from  starch  by  the 
use  of  an  acid,  and  it  is  often  utilized  for  adulterating  the 
more  costly  saccharose.    Many  seem  to  regard  glucose  as 
a  substance  deleterious  to  health,  but  in  consideration  of 
the  fact  that,  in  digestion,  starch  and  most  other  sugars 
are  reduced  to  this  compound  before  entering  the  circu- 
lation of  the  animal,  this  view  does  not  seem  to  be  sus- 
tained.  There  is  a  lack  of  evidence  to  show  the  ill  effect 
of  glucose  either  upon  man  or  animals. 

93.  Levulose. — Another   simple   sugar  is  levulose  or 
fruit-sugar,  the  composition  of  which  is  identical  with 
dextrose,  but  which  has  a  different  chemical  constitution. 
It  accompanies  dextrose  and  is  found  in  some  fruits  in 
considerable  quantities,  and  especially  in  honey.   It  is  as 
sweet  as  cane-sugar,  but  does  not  form  crystals  with  the 
same  readiness. 

94.  Galactose.— This  is  obtained  by  a  cleavage  of 
milk-sugar  (see  later)  into  this  sugar  and  dextrose.    It 
may  also  be  obtained  from  certain  gums. 


72  THE  FEEDING  OF  ANIMALS 

95.  The  pentoses. — There  are  several  pentoses,  none 
of  which  occurs  in  nature,  but  which  are  prepared  by  chem- 
ical methods  from  the  gums.    Thus,  from  gum  arabic, 
containing  araban,  arabinose  may  be  obtained,  and  from 
zylan  (wood-gum),  zylose  may  be  prepared.    Certain  of 
these  sugars  have  been  isolated  from  animal  compounds. 
They  also  have  been  found  to  appear  in  human  urine. 
They   are   important   in   the   nutrition   of   herbivorous 
animals. 

96.  Di-saccharides. — These     carbohydrates    are    all 
sugars  which  may  be  decomposed  into  two  molecules  of 
a  simple  sugar,  or  one  molecule  of  each  of  two  simple 
sugars.    They  are  only  three  in  number — saccharose  or 
sucrose  (cane-sugar),  maltose  (malt-sugar),  and  lactose 
(milk-sugar).     When  acted  on  by  weak  acids  or  cer- 
tain   ferments,    they    break    by    cleavage    (hydrolysis) 
as  follows : 

Saccharose-fwater=dextrose+levulose. 
Maltose     +water=dextrose-j-dextrose. 

Lactose      +water=dextrose+galactose. 

These  are  the  changes  that  occur  during  the  digestion 
of  food. 

97.  Saccharose. — The  most  important  of  these,  com- 
mercially considered,  is  saccharose,  which  is  the  ordinary 
crystallized  sugar  of  the  markets.   As  a  human  food  it  is 
widely  used,  is  especially  valuable,  and  its  manufacture 
and  sale  constitute  a  prominent  industry.    This  sugar  is 
obtained  mostly  from  two  plants,  sugar-cane  and  the 
sugar-beet.   It  also  exists  abundantly  in  sorghum,  pine- 
apples, carrots,  and  in  considerable  proportions  in  the 
stalk  of  ordinary  field  corn.    The  first  spring  flow  of  sap 
in  one  species  of  maple  tree  is  richly  charged  with  it. 


CARBOHYDRATES,   ACIDS,  FATS,   OILS  73 

The  fruits  generally  contain  saccharose,  mixed  with 
other  sugars  and  organic  acids,  and  upon  the  relative 
proportions  of  these  compounds  depends  the  character 
of  the  fruit  as  to  acidity  or  sweetness. 

98.  Maltose.— This  sugar  is  intimately  related  to  the 
first  growth  which  occurs  in  the  germination  of  seeds.   It 
stands  as  an  intermediate  product  between  the  store  of 
starch  in  the  seed  and  the  new  tissues  of  the  sprout.  The 
solution  that  the  brewer  extracts  from  the  malted  grains 
contains  this  compound  as  the  principal  ingredient,  and 
through  succeeding  fermentations  in  the  beer  vats  it  is 
broken  up  into  alcohol  and  other  compounds.   It  sustains 
an  important  relation,  therefore,  to  the  production  of 
beers  and  other  alcoholic  liquors.    Glucose  sirups  some- 
times contain  small  quantities  of  this  sugar.    It  is  also 
found  as  an  intermediary  product  in  the  intestinal  canal 
during  the  digestion  of  food,  being  derived  from  starch 
and  other  carbohydrates  through  the  action  of  ferments. 
Maltose  is  similar  to  cane-sugar  in  ultimate  composition, 
but  not  in  constitution,  although  as  a  nutrient  it  evidently 
has  an  equivalent  value. 

99.  Lactose. — The  only  sugar  of  animal  origin  which  is 
abundant  in  farm  life  is  the  lactose  that  is  found  in  milk, 
which  is  known  in  commerce  as  milk-sugar.   The  milk  of 
all  mammals  contains  sugar,  which  appears  to  be  the  same 
compound  with  every  species  so  far  investigated.   When 
they  are  fed  wholly  from  the  mother,  this  is  the  only 
carbohydrate   which   young  mammals   receive  in   their 
food.    The  average  proportion  of  sugar  in  the  milk  of 
domestic  animals  varies  from  three  to  six  parts  in  a  hun- 
dred, cow's  milk  containing  about  five  parts.    When  the 
cream  is  removed,  much  the  larger  part  of  sugar  remains 
in  the  skimmed  milk,  and  in  cheese-making  it  is  nearly  all 


74  THE  FEEDING  OF  ANIMALS 

found  in  the  whey,  from  which  the  milk-sugar  of  com- 
merce is  obtained.  Very  soon  after  milk  is  drawn,  unless 
it  is  heated  to  the  point  of  sterilization,  or  is  treated  with 
some  antiseptic,  the  lactose  begins  to  diminish  in  quantity, 
being  converted  into  lactic  acid  through  the  action  of 
lactic-acid  organisms  (bacteria).  Sour  milk,  therefore, 
is  different  from  sweet  in  containing  less  sugar  or  none 
at  all. 

100.  The  sugars  as  a  class. — When  considered  from 
the  standpoint  of  efficiency,  the  sugars  are  among  the 
most  valuable  of  all  the  carbohydrates,  although  in  quan- 
tity they  are  less  important  than  the  starches,  at  least 
in  raw  food  materials. 

Unlike  starch,  they  are  found  in  solution  in  the  sap  of 
growing  plants.  It  is  probable  that  these  are  the  forms  in 
which  carbohydrate  material  is  transferred  from  one  part 
of  the  plant  to  another.  It  is  easy  to  see  that  some  such 
medium  of  exchange  is  necessary.  The  actual  production 
of  new  vegetable  substance  takes  place  in  the  leaves. 
When,  therefore,  cell-walls  and  starch  grains  are  to  be 
constructed  in  the  stem  and  fruit,  the  building-material 
must  be  carried  from  the  leaves  to  these  parts  in  forms 
which  will  readily  pass  through  intervening  membranes. 
Excepting  certain  soluble  compounds,  closely  related  to 
starch,  the  sugars  appear  to  be  the  only  available  bodies 
fitted  for  this  office. 

It  is  very  seldom  that  a  plant  contains  only  a  single 
sugar.  Generally  two  or  more  sugars  are  found  together. 
This  is  especially  the  case  in  the  corn  plant,  sorghum,  and 
the  fruits,  and  the  proportions  of  each  depend  somewhat 
on  the  stage  of  growth  of  the  plant. 

101.  Other    more    complex    poly-saccharides. — This 
group  includes  a  large  number  of  carbohydrates  that  may 


CARBOHYDRATES,   ACIDS,   FATS,   OILS  75 

be  considered  as  complexes  of  the  simple  sugars  already 
described.  Indeed,  they  make  up  the  principal  bulk  of 
the  carbohydrate-content  of  cattle  foods.  These  poly- 
saccharides  may  be  divided  into  three  subgroups:  the 
starch  group,  the  gum  and  vegetable  mucilage  group,  and 
the  cellulose  group. 

102.  The  starches. — Starch  is  a  widely  distributed  and 
abundant  constitutent  of  vegetable  tissue.  Food  plants, 
especially  those  most 'used  by  the  human  family,  contain 
it  in  generous  proportions,  in  some  seeds  as  much  as  60  or 
70  per  cent  being  present.  Probably  only  water  and  cellu- 
lose are  more  abundant  in  the  vegetable  world. 

Starch  does  not  exist  in  solution  in  the  sap,  but  is 
found  in  the  interior  of  plant  cells  in  the  form  of  minute 
grains  which  have  a  shape,  size,  and  structure  character- 
istic of  the  seed  in  which  they  are  found.  Potato  starch 
grains  are  large,  about  -3^0  inch  in  diameter,  and  are  kid- 
ney-shaped, while  those  of  the  wheat  are  smaller,  about 
ToVo  inch  in  diameter,  and  resemble  in  outline  a  thick 
burning-glass.  Corn  starch  grains  are  angular,  being 
somewhat  six-sided,  and  those  of  other  seeds  show  marked 
and  specific  characteristics.  These  differences  in  size 
and  shape  furnish  the  most  important  means  of  detecting 
adulterations  of  one  ground  grain  with  another,  a  method 
much  used  in  the  inspection  of  human  and  cattle  foods. 

Unless  modified  by  some  chemical  change,  starch  is 
not  dissolved  by  water.  The  starch  grains  are  not  affected 
at  all  by  cold  water,  and,  in  hot  water,  at  first  only  swell 
and  burst.  Prolonged  treatment  with  hot  water  causes  a 
chemical  change  to  more  soluble  substances.  For  this 
reason  the  simple  leaching  of  a  food  material  removes  no 
starch  by  solution.  At  the  same  time,  the  cooking  of  a 
ground  grain  so  breaks  up  and  liberates  the  starch  grains 


76  THE  FEEDING  OF  ANIMALS 

that   they   are   probably   acted   on   more   promptly   by 
ferments  in  the  digestive  fluids. 

The  proportion  of  starch  in  plant  substances  varies 
greatly.  The  dry  matter  of  many  seeds,  such  as  rice  and 
the  cereal  grains,  wheat,  maize,  barley,  or  oats,  is  largely 
made  up  of  starch.  The  same  is  true  of  potatoes  and 
other  tubers.  Johnson  quotes  the  following  figures  from 
Dragendorff  :* 

TABLE  XXII.    AMOUNT  OF  STARCH  IN  DRY  MATTER 

Per  cent  Per  cent 

Wheat  kernel   ....       68.5  Peas       39.2 

Rye  kernel 67.  Beans 39.6 

Oat  kernel    ......       52.9  Flaxseed 28.4 

Barley  kernel  .  ^ .   .       65.  Potato  tubers       .    .    .  62.5 

It  appears  that  in  grain  plants  starch  forms  most 
abundantly  during  the  later  development  of  the  seed.  At 
the  Maine  Station  none  could  be  found  in  very  imma- 
ture field  corn  cut  August  15,  while  on  September  21 
the  dry  matter  of  the  whole  plant  on  which  the  kernels 
had  matured  to  the  hardening  stage  contained  15.4  per 
cent.  In  general,  the  stem  and  leaves  of  forage  plants  are 
poor  in  starch. 

The  distribution  of  starch  in  seeds  is  worthy  of  note. 
The  grain  of  wheat  has  been  carefully  studied  in  this 
particular,  and  it  is  found  that  this  body  does  not  nor- 
mally exist  in  the  seed  coatings,  this  tissue  consisting 
largely  of  mineral  matters,  proteins,  cellulose,  and  gums. 
On  the  contrary,  the  germ  and  interior  material  deposited 
around  it  are  rich  in  starch.  To  be  sure,  wheat  bran, 
which  is  now  very  largely  the  outer  seed  coats  of  the 
grain,  has  more  or  less,  but  this  is  due  to  imperfect  milling. 

Starch   is   an   important  commercial   article,   and   is 

*"How  Crops  Grow,"  page  52. 


CARBOHYDRATES,   ACIDS,   FATS,  OILS  77 

mainly  obtained  from  corn  and  potatoes.  Special  forms  of 
starch,  used  in  cookery  are  sago,  tapioca,  and  arrowroot. 
It  is  used  as  human  food,  as  a  source  of  dextrin,  and  in 
other  ways.  By  treatment  with  an  acid,  corn  starch  is 
converted  into  the  glucose  of  our  markets,  dextrin  and 
maltose  being  intermediate  products. 

103.  Glycogen. — This  is  the  only  uncombined  carbo- 
hydrate found  in  the  animal  body  in  appreciable  quan, 
tity  outside  the  forms  that  are  in  the  blood  circulation. 
It  is  sometimes  called  animal  starch.    It  is  a  white  pow- 
der, soluble  in  water,  and  may  be  extracted  in  small 
amounts  from  the  muscles  and  liver.    It  is  formed  out  of 
the  sugars  that  are  taken  into  the  circulation  from  the 
digestive  tract,  and,  as  we  shall  see,  is  held  a  reserve  store 
of  fuel  for  the  maintenance  of  muscular  energy,  and  in 
this  way  it  performs  a  very  important  office  in  nourishing 
the  animal  body.  (See  Par.  214.)  It  was  formerly  believed 
that  another  carbohydrate  exists  in  muscle  called  inosite, 
but  it  is  now  known  that  this  substance   belongs  to  a 
different  class  of  compounds. 

104.  The  pentosans. — These  bodies  are  very  widely 
distributed  in  nature,  being  found  in  the  leaves,  stem, 
roots,  and  seeds  of  a  great  variety  of  plants,  in  algse  and 
in  beets  and  turnips.    Certain  pentosans  are  known  as 
gums,  such  as  gum  arabic,  gum  tragacanth,  and  cherry 
gum.    Pentosans,   on  hydrolysis,   yield  pentose  sugars, 
among  which  are  arabinose  and  zylose.    These  gum-like 
substances  exist  in  beets  and  turnips  and  probably  in  all 
herbaceous  plants  that  serve  as  cattle  foods. 

105.  Galactans,  mannans,  levulans,  dextrans. — These 
are  compounds  of  some  importance  that  are  more  or  less 
associated  in  the  framework  of  a  great  variety  of  plants 
or  parts  of  plants,  including  seeds,  beets  and  turnips, 


78  THE  FEEDING  OF   ANIMALS 

tubers  and  bulbs,  algae,  lichens,  molds,  and  the  wood  and 
bark  of  many  species  of  trees.  On  hydrolysis  they  yield 
galactose,  mannose,  levulose,  and  dextrose  respectively. 
The  compounds  are  designated  as  hemi-celluloses. 

They  make  up  the  least  valuable  part  of  certain  vege- 
table foods. 

106.  The  pectin  bodies. — Another  class  of  compounds 
much  like  the  gums  and  perhaps  related  to  them  chemi- 
cally, is  the  pectin  bodies.    Some  of  these  substances  are 
gelatinous  in  appearance.    The  jellying  of  fruits,  such  as 
apples  and  currants,  is  made  possible  by  their  presence. 
They  exist  in  greater  abundance  in  unripe  fruit  than  in 
the  ripe,  consequently  the  former  is  selected  for  jelly- 
making.    When  such  fruits  are  cooked,  the  pectin  which 
they  contain  takes  up  water  chemically  and  is  transformed 
into  a  gelatinous  substance  known  as  pectose.   Mucilages 
not  greatly  unlike  the  gums  and  pectins  exist  in  certain 
seeds  and  roots,  the  most  notable  instance  being  flaxseed. 

107.  Dextrin,  which  is  sometimes  spoken  of  as  a  gum, 
is  made  by  heating  starch  to  about  200°  C.   It  may  also 
be  produced  by  treating  starch  with  a  dilute  acid.   Dex- 
trin is  formed  on  the  outer  part  of  the  loaf  when  wheat 
bread  is  baked.   It  is  soluble  in  water. 

108.  Cellulose. — This  is  found  in  the  tough  or  woody 
portion  of  plant  tissue.    In  tables  of  food  analyses  we 
find  the  term  crude  fiber,  which  consists  largely  of  cellu- 
lose, a  familiar  example  of  which  in  a  nearly  pure  form  is 
the  cotton  fiber  used  in  making  cloth.    Crude  fiber  is 
separated  from  associated  compounds  by  the  successive 
treatment  of  vegetable  substance  with  weak  acids  and 
alkalies,  and  as  so  determined  is  sometimes  improperly 
taken  to  represent  the  amount  of  cellulose  in  a  plant. 
While  crude  fiber  is  mainly  cellulose,  it  contains  a  small 


CARBOHYDRATES,   ACIDS,   FATS,   OILS  79 

proportion  of  other  compounds,  and  besides,  more  or  less 
cellulose  is  dissolved  by  the  acid  and  alkali  treatment, 
so  that  the  percentages  of  crude  fiber  given  in  food  tables 
only  approximately  measure  the  cellulose  present. 

All  plant  tissue  is  made  up  of  cells,  the  walls  of  which 
are  chiefly  or  wholly  cellulose.  It  is  this  substance  out  of 
which  is  built  the  framework  of  the  plant,  and  which 
gives  toughness  and  rigidity  to  certain  of  its  parts.  The 
more  of  this  plant  tissue  contains,  the  more  tenacious  it 
is,  other  things  being  equal,  and  the  more  difficult  of 
mastication. 

The  proportions  of  cellulose  in  the  different  parts  of  a 
plant  are  greatly  unlike.  It  is  usually  most  abundant  in 
the  stem,  with  less  in  the  foliage  and  least  in  the  fruit. 
With  vegetables  like  potatoes  and  turnips,  the  leaves  are 
much  richer  in  fiber  than  the  tubers  or  roots,  which  con- 
tain a  comparatively  small  proportion.  Of  the  grains  or 
seeds,  considerable  is  present  in  the  outer  coatings,  while 
but  little  is  found  in  the  interior.  Vegetables  such  as 
celery,  lettuce,  beets,  and  turnips  are  relatively  rich  in 
crude  fiber,  while  tubers,  flours,  and  meals  contain  only 
small  amounts.  In  certain  by-products  from  the  grains, 
like  bran,  which  is  made  up  mostly  of  the  seed  coatings, 
fiber  is  present  in  fairly  large  proportions,  while  in  flour 
derived  from  the  inner  parts  of  the  grain,  the  percentage 
is  almost  negligible. 

The  stage  of  growth  at  which  a  plant  is  used  for  food 
purposes  has  a  marked  influence  upon  the  proportion  of 
crude  fiber.  In  young,  actively  growing  vegetable  tissue, 
the  cell-walls  are  thin,  but,  as  the  plant  increases  in  age, 
these  thicken  chiefly  through  the  deposition  of  cellulose. 
In  general,  the  toughness  and  hardness  of  mature  plants, 
as  compared  with  young  are  due  to  the  increased  pro- 


80  THE  FEEDING  OF  ANIMALS 

portion  of  woody  fiber,  although  the  decrease  in  the 
relative  amount  of  water  in  the  tissues  and  the  deposition 
of  other  substances  have  more  or  less  effect. 

109.  The  acids. — Other  substances  besides  those  of  a 
carbohydrate   character   are   included   in   the  nitrogen- 
free  extract.    Chief  among  these  are  the  organic  acids, 
compounds  which  are  found  mostly  in  the  fruits,  although 
they  appear  in  certain  fermented  products,  such  as  silage 
and  sour  milk.   The  most  important  and  well  known  of 
these  are  acetic  acid,  found  in  vinegar,  citric  acid  in 
lemons,  lactic  acid  in  sour  milk,  malic  acid  in  many 
fruits,  such  as  currants  and  apples,  and  oxalic  acid  in 
rhubarb.    Sometimes  these  acids  are  free,  that  is,  not 
combined  with  any  other  compound.    In  the  main  they 
are  united  with  lime  or  some  other  base,  forming  an 
acid  salt.    Excepting  the  fruits,  only  fermented  foods 
contain  acids  to  an  appreciable  extent.  When  milk  sours, 
the  sugar  in  it  is  changed  to  lactic  acid  under  the  influence 
of  a  ferment.  The  acids  of  silage  are  formed  at  the  expense 
of  the  carbohydrates  that  are  in  the  material  which  is 
subjected  to  fermentation. 

110.  Fats  and  oils. — When  any  finely  ground  food- 
stuff, either  vegetable  or  animal,  is  submitted  to  the 
leaching  action  of  ether,   chloroform,  or  certain  other 
solvents,  several  compounds  are  taken  into  solution,  the 
main  and  important  ones  being  fats  or  oils.  These  bodies 
make  up  the  chief  portion  of  such  an  extract  from  seeds, 
while  the  extract  from  other  vegetable  materials  also 
contains  a  considerable  amount  of  wax,  chlorophyl,  and 
other  substances.    Tables  that  show  the  composition  of 
foods   have   a   column   which   is   sometimes   designated 
"ether-extract,"  and  sometimes  "fats  or  oils."  The  former 
is  the  more  accurate  term,  because  the  compounds  which 


CARBOHYDRATES,  ACIDS,   FATS,   OILS  81 

it  is  the  intention  to  describe  are  often  no  more  than  half 
fats  or  oils.  The  real  value  of  the  ether-extract  from 
different  foods  is  partly  determined,  therefore,  by  its 
source.  When  it  is  all  oil,  or  nearly  so,  it  is  worth  much 
more  for  use  by  the  animals  than  when  it  is  made  up  to 
quite  an  extent  of  other  compounds. 

111.  Fats  or  oils  in  grains  and  seeds. — The  propor- 
tions of  fat  or  oil  in  cattle  foods  vary  within  wide  limits. 
In  general,  seeds  and  their  by-products  contain  more  than 
the  stem  and  leaves,  the  differences  in  the  percentages  of 
actual  oil  being  greater  than  is  indicated  by  the  ether- 
extract.  But  little  is  found  in  the  dry  matter  of  roots 
and  tubers.  Among  the  cereal  grains  and  other  more 
common  farm  seeds,  corn  and  oats  show  the  largest 
amounts,  the  proportion  in  dry  matter  being  from  5  to  6 
per  cent,  while  wheat,  barley,  rye,  peas,  and  rice  contain 
much  smaller  percentages,  wheat  having  about  2  per 
cent,  and  rice  sometimes  not  over  one-fifth  of  1  per  cent. 
Agricultural  seeds  that  are  especially  oleaginous  are 
cottonseed,  flaxseed,  sunflower  seeds,  and  the  seeds  of 
many  species  belonging  to  the  mustard  family,  such  as 
rape.  Peanuts,  coconuts,  and  palm  nuts  are  also  very 
rich  in  oil.  The  average  percentages  in  these  seeds  and 
nuts  are  approximately  as  given  below: 

TABLE  XXIII.    OIL  IN  CERTAIN  SEEDS 


Linseed 

Per  cent 

34 

Peanuts     .    . 

Per  cent 

....        46 

Cottonseed 

30 

Coconuts 

....        67 

Sunflower  seed     . 
Rape  seed     .    .    . 

,    .        32 
.    .        42 

Palm  nuts     . 
Poppy  seed 

....        49 
....        41 

Mustard  seed  . 

32 

The  oils  from  all  the  above  are  important  commercial 
products,  being  used  in  a  great  variety  of  ways  in  human 


82  THE  FEEDING  OF  ANIMALS 

foods  and  in  the  arts.  In  many  cases,  the  refuse  from  this 
extraction  goes  back  to  the  farm  as  food  for  cattle.  This 
is  especially  true  of  linseed  and  cottonseed. 

112.  Nature  and  kinds  of  fats. — The  vegetable  and 
animal  fats  and  oils  may,  for  convenience'  sake,  be  dis- 
cussed in  two  divisions,  the  neutral  fats,  or  glycerides,  and 
the  fatty  acids.   The  neutral  fats  are  combinations  of  the 
fatty  acids  with  glycerin.    When,  for  instance,  lard  is 
treated  at  a  high  temperature  with  the  alkalies,  potash 
and  soda,  glycerin  is  set  free,  and  an  alkali  takes  its  place 
in  a  union  with  the  fatty  acids.    This  is  the  chemical 
change  which  occurs  in  soap-making.    There  are  several 
of  these  neutral  fats,  the  ones  most  prominent  and  impor- 
tant in  agriculture  being  those  abundant  in  butter  and 
in  the  body  fats  of  animals,  viz.,  butyrin,  caproin,  cap- 
rylin,    caprin,    laurin,    myristin,    olein,    palmatin,    and 
stearin,  the  last  three  being  the  most  abundant  and  impor- 
tant in  human  foods.    Butyrin  is  a  combination  of  buty- 
ric acid  and  glycerin,  stearin  of  stearic  acid  and  glycerin, 
and   so   on.     Because  these  are  combinations  of  three 
molecules  of  a  fatty  acid  radical  with  one  of  glycerin, 
they  are  sometimes  named  tri-stearin,  tri-palmatin,  and 
tri-olein,  and  so  on.    Some  single  fats   (glycerides)  are 
compounds  of  two  or  three  fatty  acid  radicals  united  with 
glycerin  in  the  same  molecule.   As  glycerin  is  an  alcohol, 
and  as  combinations  of  an  alcohol  and  acids  are  ethers, 
the  neutral  fats  are  really  ethers  (esters),  although  they 
differ  greatly  from  the  common  conception  of  an  ether 
which  is  gained  from  ethyl  ether  or  the  ether  of  drug-stores. 

113.  Physical  properties  of  the  fats  and  oils. — These 
individual  fats  possess  greatly  unlike  physical  properties. 
They  are  all  soluble  in  benzine,  chloroform,  and  ether, 
and  insoluble  in  water.    At  the  ordinary  temperature  of 


CARBOHYDRATES,   ACIDS,   FATS,   OILS  83 

a  room,  some  are  liquid  and  some  are  solid,  olein  belong- 
ing to  the  former  class,  and  palmatin  and  stearin  to  the 
latter.  Butter,  lard,  and  tallow  differ  in  hardness  at  a 
given  temperature,  and  it  may  easily  be  discovered  that 
their  melting-points  are  not  the  same.  As  the  animal 
body  fats  are  in  all  cases  chiefly  mixtures  of  olein,  palma- 
tin, and  stearin,  stearin  and  palmatin  being  a  solid  at 
ordinary  temperatures,  and  olein  a  liquid  at  anything 
above  the  freezing-point,  it  is  evident  that  the  relative 
proportions  of  these  compounds  will  affect  the  ease  of 
melting  and  the  hardness  of  the  mixtures  of  which  they 
are  a  part.  Stearin  melts  at  71.7°  C.  and  palmatin  at 
62°  C.  Tallow,  having  much  more  stearin  than  lard  and 
less  olein,  is  consequently  much  more  solid  on  a  hot  day. 

The  composition  and  physical  properties  of  the  fat 
from  a  beef  animal  seem  to  vary  according  to  the  age  of 
the  animal  and  the  locality  of  the  body  from  which  the 
fat  is  taken.  Fat  from  an  old  animal  melts  at  a  lower 
temperature  than  that  from  a  young  animal,  and  the 
same  is  true  of  fat  taken  from  the  outside  of  the  body  as 
compared  with  that  taken  from  the  inside.  Fat  from 
the  herbivora  is  in  general  harder  than  that  from  the 
carnivora. 

114.  Milk -fat. — This  contains  not  only  the  three 
principal  fats,  but  also  the  others  mentioned,  butyrin, 
caprion,  caprylin,  caprin,  laurin,  and  myristin,  in  small 
proportions,  and  these  latter  tend  to  give  butter  certain 
properties  that  distinguish  it  from  the  other  animal  fats, 
which  are  almost  wholly  palmatin,  olein,  and  stearin. 
These  special  butter-fats  are  liquid  at  ordinary  tempera- 
tures. Doubtless  the  flavor,  texture,  and  resistance  of 
butter  to  the  effects  of  heat,  are  much  influenced  by  the 
proportions  of  the  numerous  fats  it  contains. 


84 


THE  FEEDING  OF  ANIMALS 


115.  Fatty  acids. — Free,  fatty  acids  exist  in  nature. 
They  are  not  found  in  butter,  lard,  and  tallow  unless 
these    substances    have    undergone    fermentations    and 
become  rancid.   The  characteristic  flavor  of  strong  butter 
is  due  to  free  butyric  acid,  which,  because  of  fermenta- 
tions, has  parted  from  the  glycerin  with  which  it  was 
originally  combined  in  the  milk.    In  plant  oils,  on  the 
other  hand,  are  found  considerable  proportions  of  the 
free  fatty  acids,  some  of  which  have  not  been  discovered 
so  far  in  animal  fats,  either  free  or  uncombined. 

116.  Ether-extracts. — Stellwaag  investigated    the   in- 
gredients of  the  ether-  and  benzine-extracts  from  plants. 
His  results  show  that  not  only  do  these  extracts  include 
substances  which  are  not  fats,  but  that  a  considerable 
proportion  of  free,  fatty  acids  is  always  present,  sometimes 
in  quantities  exceeding  the  neutral  fats: 

TABLE  XXIV.    COMPOSITION  OF  ETHER-EXTRACTS 


Neutral 
fats 

Free  fatty 
acids 

Material    not 
saponifiable 

Potatoes    

Per  cent 

16.3 

Per  cent 
56.9 

Per  cent 
10.9 

Beets     .    . 

23. 

353 

107 

Maize,  kernel  .    .    .    .    .    .    :    . 

88.7 

6.7 

3.7 

Barley  . 

73 

14. 

6  1 

Oats      

61.6 

27.6 

2.4 

It  appears,  as  before  stated,  that  ether-extract,  espe- 
cially that  from  vegetables,  may  consist,  to  some  extent,  of 
materials  which  should  not  be  classed  among  the  fats. 
The  extracts  from  the  grains  proved  to  be  nearly  all  oil. 
Moreover,  the  grain  oils  were  made  up  principally  of  gly- 
cerides,  and  those  from  potatoes  and  beets  consisted 
largely  of  free,  fatty  acids. 


CARBOHYDRATES,  ACIDS,  FATS,  OILS  85 

117.  Lecithins. — These    are    often    called    the    phos- 
phorized  fats.    It  has  previously  been  stated  that  neutral 
fats  are  combinations  of  fatty  acids  and  glycerin  (glycerol). 
Lecithins  are  compounds  in  which  one  of  the  radicals 
of  a  fatty  acid  is  replaced  by  a  compound  of  phosphorus. 
They  are  widely  distributed  in  nature.    They  appear  to 
be  an  active  component  of  every  cell,  both  of  vegetable 
and  animal  tissue,  and  they  are  especially  abundant  in 
seeds,  in  the  nerve  system,  in  fish,  eggs,  and  in  the  yolk 
of  eggs.    These  compounds  evidently  fill  an  important 
place  in  plant  and  animal  nutrition.    There  are  good 
theoretical  reasons  for  suggesting  that  lecithins  serve  as 
a  stepping-stone  to  the  synthesis  of  the  nucleo-proteins. 
In  digestion  they  behave  like  the  true  fats. 

118.  Enzyms,      anti-bodies,      hormones,      vitamines 
(accessories). — The  science  of  nutrition  must  now  deal 
with  a  class  of  bodies  which  have  not  been  isolated,  some 
of  which  have  merely  a  theoretical  standing,  and  all  of 
which  are  known  chiefly  by  their  reactions. 

Certain  of  these  bodies  are  formed  within  the  animal 
organism  and  others  are  associated  with  foods. 

The  subject  of  enzyms  is  treated  in  Par.  128. 

Anti-bodies  are  bodies  which  in  some  manner  neu- 
tralize or  hinder  the  specific  action  of  some  other  body, 
as  for  instance  the  anti-enzyms.  It  is  held  that  an  anti- 
pepsin  exists  in  the  mucous  membranes  of  the  stomach 
and  an  anti-trypsin  in  the  mucous  membrane  of  the 
intestine  which  render  these  linings  immune  to  the 
action  of  the  digestive  juices. 

Hormones,  or  "chemical  messengers"  are  represented 
by  secretin  (see  Par.  161)  which  reacts  upon  certain 
secretory  glands,  as  for  instance  the  pancreas,  causing  a 
flow  of  the  digestive  fluid.  The  formation  of  secretin  is 


86  THE  FEEDING  OF  ANIMALS 

believed  to  be  due  to  the  reaction  of  certain  food  sub- 
stances on  the  inner  membranes  of  the  stomach. 

Vitamines,  or  food  accessories,  are  regarded  as  being 
attached  to  foods,  and  may  properly  be  styled  growth- 
promoting  substances.  These  bodies  of  an  unknown 
nature  seem  to  fall  into  two  classes  (Hart  and  McCollum), 
the  fat-soluble  accessory  attached  to  butter  fat,  egg  yolk 
fat,  pig  kidney  fat,  and  certain  vegetable  fats,  and  a 
water-soluble  accessory  attached  to  the  wheat  embryo, 
egg  yolk,  milk-powder,  and  other  foods.  These  accessories 
are  not  destroyed  by  heat,  even  when  subjected  to  the 
action  of  steam  for  two  and  one-half  hours.  The  fat 
soluble  accessory  may  be  concentrated  in  butter  oil  by 
fractional  crystallization  of  the  harder  fats. 


CHAPTER  VII 
THE  DIGESTION  OF  FOOD 

WE  have  accepted  so  far  without  discussion  the  almost 
self-evident  fact  that  the  food  is  the  immediate  source 
of  the  substance  and  energy  of  the  animal  body.  It  now 
remains  for  us  to  consider  the  way  in  which  nutrition  is 
accomplished.  The  first  step  in  this  direction  is  the  diges- 
tion of  food.  It  is  necessary  for  food  ingredients  to  be 
placed  in  such  relations  to  the  animal  organism  that  they 
are  available  for  use.  This  involves  both  condition  and 
location.  The  various  nutrients  in  the  exercise  of  their 
several  functions  must  be  generally  distributed,  and  so 
their  compounds,  in  part  at  least,  must  be  brought  into 
soluble  and  diffusible  condition,  in  order  that  they  may 
pass  through  the  membranous  lining  which  separates  the 
blood  vessels  and  other  vascular  bodies  from  the  cavity 
of  the  alimentary  canal. 

119.  Digestion  vs.  assimilation. — In  discussing  physio- 
logical relations  of  food,  two  terms  are  employed,  viz., 
digestion  and  assimilation.  Digestion  refers  to  the 
preparation  of  food  compounds  for  use,  by  rendering 
them  soluble  and  diffusible — changes  which  are  accom- 
plished in  what  we  call  the  alimentary  canal,  a  passage 
that  begins  with  the  mouth,  includes  the  stomach  and 
intestines,  and  ends  with  the  anus.  Assimilation  signifies 
the  appropriation  of  nutrients,  after  digestion,  to  the 
maintenance  of  the  vital  processes  and  to  the  building 
of  flesh  and  bone — processes  taking  place  in  the  tissues, 

(87) 


88  THE  FEEDING  OF  ANIMALS 

to  which  the  nutritive  substances  are  conveyed  by  the 
blood.  The  two  terms  are  entirely  distinct  in  meaning, 
although  they  are  confused  in  popular  speech. 

120.  General  changes  in  food  through  digestion. — 
In  digestion,  food  undergoes  both  mechanical  and  chemi- 
cal changes.  It  is  masticated,  that  is,  ground  into 
finer  particles,  after  which,  in  its  passage  along  the 
alimentary  canal,  it  comes  in  contact  with  several 
juices  which  profoundly  modify  it  chemically.  That 
portion  of  it  which  is  rendered  diffusible  is  absorbed 
by  certain  vessels  that  are  embedded  in  the  walls  of 
the  stomach  and  intestines,  and  is  conveyed  into  the 
blood.  The  insoluble  part  passes  on  and  is  rejected  by 
the  animal  as  worthless  material,  and  constitutes  part 
of  the  solid  excrement  or  feces.  The  forms  in  which  the 
nutrients  are  conveyed  into  the  circulation  are  believed 
to  be  the  following:  The  proteins,  previous  to  absorption 
into  the  blood,  are  converted  into  soluble  bodies,  at 
first  proteoses  and  peptones,  and  finally  into  simpler 
nitrogen  compounds  (amino  acids)  resulting  from  a  more 
extensive  cleavage;  the  carbohydrates  enter  the  blood 
as  sugars,  chiefly  as  dextrose.  The  fats  are  changed  into 
a  finely  divided  form,  either  as  such  or  as  fatty  acids  and 
soaps.  A  study  of  digestion  includes,  then,  a  knowledge 
of  mastication,  of  the  sources,  nature,  and  functions  of 
the  several  digestive  juices,  and  a  consideration  of  the 
various  conditions  affecting  the  extent  and  rapidity  of 
digestive  action. 

FERMENTS 

The  changes  involved  in  rendering  food  compounds 
soluble  are  intimately  connected  with  a  class  of  bodies 


A  dairy  mother — Guernsey. 


Well-fed  Hereford  heifer. 
PLATE  III.    Two  good  bovine  types. 


THE  DIGESTION  OF  FOOD  89 

known  as  ferments,  and  it  seems  necessary  before  proceed- 
ing to  a  consideration  of  digestion  as  a  process  to  learn 
something  of  the  nature  and  function  of  these  agents,  which 
are  actively  and  essentially  present  in  the  digestive  tract. 

121.  Definition    of    ferments. — A    ferment    may    be 
defined  in  a  general  way  as  an  agent  which  causes  the 
decomposition  of  certain  vegetable  or  animal  compounds 
with  which  it  comes  in  contact  under  favorable  condi- 
tions.  In  the  past,  ferments  have  been  classified  into  two 
kinds,  organized  and  unorganized.    The  so-called  organ- 
ized ferments  are  low,  microscopic  forms  of  vegetable  life, 
generally  single-celled  plants.    The  unorganized  ferments 
are    not    living    organisms,    but    are    simply    chemical 
compounds. 

122.  Organized  ferments. — When  milk  is  allowed  to 
remain  in  a  warm  room  for  several  hours,  it  becomes 
sour.    An  examination  of  it  chemically  shows  that  its 
sugar  has  in  part  disappeared  and  has  been  replaced  by 
an  acid.   A  study  of  the  milk  with  the  microscope,  before 
and  after  souring,  reveals  the  fact  that  there  has  been  a 
marvelous  increase  in  it  of  single-celled  organisms  or 
plants.    The  presence  of  this  form  of  life  is  regarded  as 
the  cause  of  the  change  of  the  sugar  into  lactic  acid.   We 
have  here  a  so-called  lactic-acid   ferment,  which  may 
typify  the  organized  ferments  known  as  bacteria.  Numer- 
ous other  fermentations  of  the  same  general  kind  are 
common  to  everyday  experience,  such  as  the  changes  in 
the  cider  barrel  and  the  wine  cask,  the  spoiling  of  canned 
fruits  and  vegetables,  and  the  heating  of  hay  and  grain, 
which  are  all  illustrations  of  what  is  accomplished  by  these 
minute  organisms. 

123.  Structure  and  distribution  of  organized  ferments. 
— The  organized  ferments  are  classed  in  the  vegetable 


90  THE   FEEDING   OF   ANIMALS 

kingdom.  As  a  rule,  each  individual  plant  is  a  single 
cell  and  so  minute  as  to  be  invisible  to  the  unaided  sight. 
It  corresponds  in  its  general  structure  to  the  cells  which 
make  up  the  tissues  of  the  higher  vegetable  species,  i.  e., 
it  consists  of  a  cell  wall  inside  of  which  are  protoplasm 
and  other  forms  of  matter.  These  organisms  are  dis- 
tributed everywhere — in  the  air,  in  the  soil,  on  surfaces 
of  plants,  and  in  the  bodies  of  animals.  Whenever  the 
right  opportunity  offers  itself,  they  multiply  and  bring 
about  all  the  results  attendant  upon  their  growth. 

124.  Conditions  of  growth  of  organized  ferments. — 
The  conditions  essential  to  their  development  are  the 
proper  degree  of  moisture  and  temperature  and  the  neces- 
sary food  materials.  Animal  and  vegetable  substances 
supply  the  necessary  nutrients,  but  when  thoroughly  dry 
do  not  ferment.  Flour  and  meal  that  have  been  dried  to 
a  water-content  of  10  per  cent  will  keep  a  long  time  with- 
out loss  from  fermentative  changes.  The  heat  in  a  mow 
of  hay  or  in  a  bin  of  new  grain,  with  their  subsequent 
musty  condition,  is  due  to  the  fermentations  that  are 
made  possible  through  the  presence  of  considerable 
moisture.  Thorough  drying  is  a  preventive  of  these 
destructive  fermentations. 

There  is  a  temperature  at  which  each  vegetable  ferment 
thrives  best,  and  there  are  limits  of  temperature  outside 
of  which  the  growth  of  these  forms  of  life  does  not  occur, 
or  is  very  slight.  Numerous  species  thrive  between  75°  and 
100°  F.  Fermentable  materials  like  fruit  and  meat  at 
the  freezing-point  or  below  are  not  subject  to  fermenta- 
tions. The  boiling-point  of  water  kills  most  bacteria, 
and  temperatures  above  150°  F.  retard  or  entirely  pre- 
vent their  growth. 


THE  DIGESTION  OF  FOOD  91 

125.  Results    of   fermentation. — Like   all   life,    these 
organisms  must  have  food.    Many  species  find  this  in 
acceptable    forms    in    vegetable    and    animal    products. 
Because  these  products  contain  the  sugar,  proteins,  and 
mineral   compounds   which   nourish   bacteria,   many   of 
them  are  the  prey  of  ferments  under  proper  conditions  of 
moisture  and  temperature.   The  prevention  of  fermenta- 
tion in  cattle  foods  is  desirable  because  it  occasions  a  loss 
of  nutritive  value  and  often  produces  undesirable  flavors. 
The  loss  becomes  evident  when  we  consider  the  nature  of 
the  chemical  changes  that  occur.   For  instance,  when  the 
sugars  in  cider  are  broken  up  through  the  influence  of  a 
bacterium,  carbon  dioxid  and  alcohol  are  formed  through 
the  appropriation  of  free  oxygen.   This  means  that  com- 
bustion occurs,  causing  the  liberation  of  energy  which 
otherwise  would  have  been  available  if  the  sugar  had 
been  taken  as  food.    Many  other  fermentations  involve 
oxidation,  all  of  which  are  destructive  of  food  value. 

126.  Manner    of    action    of    ferments. — These    little 
plants  use  sugar  and  other  compounds  as  food,  deriving 
energy  and  growth  therefrom,  the  carbonic  acid,  alcohol, 
and  other  new  bodies  being  the  by-products  of  this  use. 
It  now  appears  probable  that  these  organisms  develop  an 
unorganized  ferment  which  brings  about  these  fermen- 
tative changes.    Indeed,  it  is  definitely  proved  that  it  is 
possible  to  separate  from  the  cells  of  the  yeast  plant  a 
substance  that,  in  the  absence  of  the  yeast  plant  itself, 
converts  sugar  into   carbon  dioxid   and   alcohol.    This 
shows  that  the  effective  agent  in  bacterial  fermentations 
is,  after  all,  a  chemical  substance,  or  an  unorganized 
ferment.   These  later  discoveries  tend  to  remove  the  dis- 
tinction that  has  been  made  between  the  so-called  organ- 
ized  and   unorganized   ferments.     Certain  ferments  are 


92  THE  FEEDING  OF  ANIMALS 

among  the  most  useful  agencies  with  which  we  deal  and 
some  are  harmful.  The  yeast  plant  is  useful  in  bread- 
making,  but  the  putrefaction  of  meats  under  the  influence 
of  another  ferment  causes  loss. 

127.  Bacteria  in  the  digestive  tract. — The  digestive 
tract  of  animals  is  inhabited  by  countless  numbers  of 
bacteria.   These  inhabit  both  the  stomach  and  the  intes- 
tines, especially  the  colon.   They  also  form  a  part  of  the 
feces.   The  two  main  types  in  which  we  are  interested  in 
their  relation  to  digestion  are  (1)  the  fermentative  or  those 
that  attack  the  carbohydrates,  especially  the  sugars,  and 
(2)  the  putrefactive,  or  those  that  cause  decomposition  of 
the  proteins.   Under  certain  conditions  such  as  a  sudden 
change  of  food  to  large  amounts  of  young  and  succulent 
herbage,  especially  the  legumes,  bacterial  fermentations 
may  endanger  the  life  of  the  animal  through  the  exces- 
sive formation  of  acids  and  gases. 

128.  Unorganized  ferments. — There  is  another  class  of 
ferments  which  is  termed  unorganized,  and  to  which  the 
general  term  "enzym"  is  given.    These  are  the  ferments 
especially  important  in  digestion.   They  are  merely  chemi- 
cal compounds,  formed  within  the  living  cells  of   the 
plant  or  animal,  which  produce  a  peculiar  effect   upon 
certain  bodies  with  which  they  come  in  contact.    If  a 
thin  piece  of  lean  beef  be  suspended  in  an  extract  from 
the  mucous  lining  of  a  pig's  stomach,  to  which  has  been 
added  a  small  proportion  of  hydrochloric  acid,  the  liquid 
being  kept  at  about  98°  F.,  the  beef  will  soon  begin  to 
soften,  afterwards  swell  to  a  more  or  less  jelly-like  con- 
dition,  and  finally  dissolve.    The  same  general  result 
would  occur  with  fish,  blood  fibrin,  or  the  coagulated 
white  of  an  egg.   When  starch  is  placed  in  a  warm-water 
solution  of  crushed  malt,  it  soon  dissolves,  leaving  a  com- 


THE  DIGESTION  OF  FOOD  93 

paratively  clear  liquid.  A  chemical  examination  of  these 
preparations  will  reveal  the  fact  that  the  compounds  of 
the  meat  are  present  in  solution  in  somewhat  modified 
forms,  and  that  the  starch  has  been  changed  to  a  sugar 
or  other  soluble  bodies.  In  both  cases  substances  insolu- 
ble in  water  have  become  soluble  and  diffusible. 

129.  Enzyms  and  their  action. — The  cause  of  these 
changes  is  the  presence,  one  in  the  pig's  stomach  and  one 
in  the  malt,  of  ferments  of  the  enzym  class,  the  former  of 
which  renders  proteins  soluble,  the  latter  producing  a 
similar  result  with  the  insoluble  carbohydrates.  This 
action  is  not  entirely  like  that  caused  by  the  presence  of 
the  organized  ferments,  where  oxidation  occurs  in  many 
cases.  The  enzyms  simply  induce  the  proteins  and  starch 
to  take  up  the  elements  of  water,  a  change  which  is  termed 
hydrolysis.  How  this  is  done  cannot  be  explained  in 
simple  terms,  if  at  all.  Our  knowledge  of  the  manner  of 
the  change  rests  to  some  extent  upon  theoretical  grounds. 
Enzyms  are  regarded  as  catalyzers,  that  is,  compounds 
which  by  their  presence  cause  chemical  changes  while 
they  themselves  do  not  enter  into  the  combinations 
formed.  A  small  quantity  of  an  enzym  may  cause  changes 
in  a  large  amount  of  material,  the  enzym  itself  under- 
going no  appreciable  change.  The  digestion  of  food  is 
largely  accomplished  through  the  specific  effect  of  enzyms, 
of  which  every  digestive  fluid  contains  one  or  more.  Exam- 
ples of  these  are  the  pepsin  and  pancreatin  of  the  drug- 
store that  contain  enzyms  mixed  with  more  or  less  of 
impurities.  The  various  enyzms  are  often  given  names 
according  to  their  function:  invertase,  which  inverts  or 
splits  sucrose;  glucose,  that  changes  any  carbohydrate 
into  glucose  (also  called  maltase);  lactase,  that  splits  lac- 
tose into  simpler  sugars.  In  general,  the  ferments  acting 


94  THE  FEEDING  OF  ANIMALS 

on  starch  are  called  diastases.  Enzyms  that  split  fats  are 
designated  as  Upases  and  those  acting  on  proteins  to  pro- 
duce proteoses  are  designated  as  proteases. 

THE  ALIMENTAKY   CANAL 

The  digestion  of  food  is  accomplished  in  the  alimen- 
tary canal,  a  duct  that  extends  from  the  mouth  to  the 
anus. 

130.  Parts  of  the  alimentary  canal. — The  succession  of 
the  various  parts  of  this  canal  is  as  follows:  the  esophagus, 
stomach,  small  intestine  (duodenum)  and  the  large  intes- 
tine (colon). 

The  length  of  the  intestines  in  the  several  species  of 
farm  animals  is  very  great  as  compared  with  the  length 
of  the  body  of  the  animal,  as  the  following  figures  show: 

Sheep,  ratio  length  of  intestine  to  length  of  body  .  26  times 

Ox,  ratio  length  of  intestine  to  length  of  body    .  .  20  times 

Horse,  ratio  length  of  intestine  to  length  of  body  .  12  times 

Dog,  ratio  length  of  intestine  to  length  of  body  .  3  times 

The  food  is  pushed  along  the  intestinal  canal  by  a 
muscular  movement  of  the  walls  of  the  intestines  known 
as  peristalsis,  which  passes  from  stomach  to  rectum,  being 
slower  in  the  large  intestine  than  in  the  small.  During  this 
passage  there  occurs  both  the  digestion  of  food  and  the 
absorption  through  the  walls  of  the  canal  of  the  digested 
materials. 

THE  MOUTH 

131.  Mastication. — The  first  step  in  the  digestion  of 
fodders  and  whole  grains  is  to  reduce  them  to  a  much 
finer  condition.  This  is  done  in  the  mouth,  the  teeth  being 
the  grinding-tools.*   Sometimes  the  cutting  or  grinding  is 

*This  is  not  true  of  hens,  turkeys,  and  other  fowls. 


THE  DIGESTION  OF  FOOD  95 

partially  or  wholly  performed  for  the  animal  in  hay- 
cutters  and  grain  mills.  This  mastication  is  essential  for 
two  reasons:  (1)  It  puts  the  food  in  condition  to  be  swal- 
lowed, and  (2)  fits  it  for  the  prompt  and  efficient  action 
of  the  several  digestive  fluids.  Dry  whole  hay  or  kernels 
of  grain  could  hardly  be  forced  down  the  tube  leading  to 
the  animal's  stomach.  It  is  necessary  for  these  mate- 
rials to  be  broken  down  and  moistened  in  order  that  they 
may  be  swallowed.  Even  if  they  could  be  conveyed  to  the 
stomach  in  their  natural  condition  the  process  of  render- 
ing their  constituents  soluble  would  proceed  very  slowly. 
The  more  finely  any  solid  is  ground,  the  larger  is  the  sur- 
face exposed  to  the  attack  of  the  dissolving  liquid  and 
the  more  rapid  the  action. 

132.  The  teeth. — Prompt  and  rapid  solution  of  food 
is  essential,  because,  if  it  is  too  long  delayed,  uncomforta- 
ble and  injurious  fermentations  are  likely  to  set  in,  and, 
because  of  imperfect  digestion,  the  final  nutritive  effect 
of  the  ration  may  be  diminished.  For  these  reasons, 
animals  with  diseased  teeth,  or  those  that  have  lost  teeth, 
make  poor  use  of  their  food,  and  require  an  unnecessary 
amount  to  keep  them  in  condition.  These  conditions 
may  often  be  a  cause,  especially  with  horses,  of  disappoint- 
ing results  from  an  ordinarily  sufficient  ration.  The  teeth 
of  our  domestic  animals  differ  somewhat  in  number  and 
arrangement.  Authorities  state  the  following  to  be  the 
usual  number: 

TABLE  XXV 

Total         Incisors        Canines      Molars 

Horse              36-40  12  4            24 

Ox 32  8  24 

Sheep  and  goat 32  8  24 

Pig 44  12  4  28 


96  THE  FEEDING  OF   ANIMALS 

The  incisors  or  front  teeth  are  those  which  are  used 
for  prehension,  and  by  grazing  animals  for  cutting  off  the 
grass  and  other  herbages.  With  the  ox,  sheep,  and  goat, 
incisors  are  found  only  in  the  lower  jaw.  These  move  in 
their  sockets  and  shut  against  a  tough  pad  on  the  upper 
jaw.  They  are  constantly  being  pushed  out  of  their 
sockets  and  wearing  off,  and  with  old  animals  may  be 
so  worn  away  as  to  leave  only  the  roots.  Such  animals  do 


FIQ.  1.   Glands  secreting  saliva  in  man, — parotid,  sublingual, 
subm  axillary. 

not  graze  successfully.   With  the  horse  and  pig,  incisors 
are  found  in  equal  numbers  in  both  jaws. 

The  molars  are  the  grinding  teeth.  Those  of  the  horse 
sometimes  need  filing  on  the  edges  in  order  to  prevent 
irritation  and  soreness  of  the  adjacent  tissues.  A  diseased 


THE  DIGESTION  OF  FOOD  97 

molar  may  also  occasion  an  animal  much  discomfort  and 
cause  imperfect  mastication. 

133.  The  saliva. — During  mastication  there  is  poured 
into  the  mouth  a  liquid  called  the  saliva,  which  has  two 
important  functions:  (1)  It  moistens  the  food,  and  (2) 
with   several   species   of   animals   it   causes  a  chemical 
change  in  certain  of  the  constituents  of  the  food. 

134.  Origin  of  saliva. — The  saliva  has  its  origin  in 
several  secretory-glands  that  are  adjacent  to  the  mouth 
cavity,  and  from  these  this  liquid  is  poured  into  the 
mouth  through  ducts  that  open  in  the  cheek  and  under 
the  tongue  (Fig.  1).  The  chief  of  these  glands  are  located  in 
the  side  of  the  face,  below  and  somewhat  back  of  the  jaws 
and  beneath  the  tongue,  and  are  called  respectively  the 
parotid,  the  submaxillary,   and   the  sublingual.    Other 
glands  of  this  character  are  scattered  in  the  cheeks  and 
at  the  base  of  the  tongue.  The  proportions  of  these  glands 
in  the  several  species  of  farm  animals  are  as  follows: 

TABLE  XXVI 

Horse  Ox  Sheep  Pig  Dog 

Parotid    ....      78  45  52  81  48 

Submaxillary      .      17  48  43  16  52 

Sublingual      .    .        5  7  5  3 

135.  Properties  and  office  of  saliva. — The  saliva  is  a 
transparent  and  somewhat  slimy  liquid,  and  contains 
generally  not  less  than  ninety-nine  parts  in  one  hundred 
of  water,  and  one  part  or  less  of  solid  matter.   It  is  alka- 
line in  reaction,  because  of  the  presence  of  compounds 
of  the  alkalies.   One  important  organic  compound  present 
is  mucin.    The  specific  chemical  effect  exerted  by  this 
liquid  on  the  food  constituents  may  be  illustrated  by  sub- 
jecting starch  to  its  action.  When  this  is  done,  the  starch 
gradually  disappears  as  such  and  is  replaced  by  dextrin 


98  THE  FEEDING  OF  ANIMALS 

and  maltose,  chiefly  the  latter.  The  agent  which  is  active 
in  causing  this  change  is  an  enzym  (see  Par.  128),  to 
which  the  name  ptyalin  has  been  given,  and  which  is 
always  present  in  the  saliva  of  man  and  of  some  animals. 
It  is  classed  among  the  diastatic  ferments,  and  has  an 
office  similar  to  that  of  diastase  in  the  germination  of 
seeds,  viz.,  the  transformation  of  starch  into  a  sugar. 
With  man  this  change  begins  in  the  mouth  and  continues 
in  the  stomach  until  the  food  becomes  so  acid  that  the 
ferment  ceases  to  act,  for  ptyalin  is  inactive  except  in  an 
alkaline  medium.  There  is  yet  no  reason  for  concluding 
that  with  herbivora  the  saliva  is  as  important  in  car- 
bohydrate digestion  as  with  man.  Different  observers 
differ  in  opinion  as  to  the  diastatic  value  of  saliva  with 
farm  animals. 

The  saliva  also  moistens  the  food,  which  is  a  most 
important  office,  for  it  is  a  necessary  preparation  to  the 
act  of  swallowing.  The  saliva  is  not  the  same  from  the 
different  glands,  that  from  the  parotid  being  watery  with 
no  mucin  and  that  from  the  other  glands  being  rich  in 
mucin  and  therefore  very  viscid.  The  former  serves 
chiefly  to  moisten  the  food  while  the  latter  aids  in  swal- 
lowing. 

136.  Quantity  of  saliva  excreted. — With  large  rumi- 
nants, the  quantity  of  saliva  required  is  large,  as  is  evi- 
dent when  we  remember  that  an  ox  or  cow  may  consume 
in  one  day  twenty-four  pounds  of  very  dry  hay  and  grain, 
and  that  rumination  goes  on  much  of  the  time  while  the 
animal  is  not  eating.  It  is  estimated  that  oxen  and 
horses  secrete  from  eighty-eight  to  one  hundred  and  thirty- 
two  pounds  daily,  an  apparently  enormous  quantity 
of  liquid  for  organs  no  larger  than  the  salivary  glands 
to  supply.  The  extent  and  character  of  the  secretion  of 


THE  DIGESTION  OF  FOOD  99 

saliva  seems  to  be  modified  by  the  nature  of  the  food 
offered,  dry  materials  stimulating  the  parotid  gland  and 
moist  foods  only  the  submaxillary  and  sublingual.  The 
organic  constituents  of  the  saliva  are  the  peculiar  prod- 
ucts of  the  secretory  activity  of  the  cells  of  the  salivary 
glands,  and  the  water  and  inorganic  salts  are  regarded 
as  the  result  of  cell  secretion. 

THE  STOMACH 

When  the  food  leaves  the  mouth,  it  passes  down  the 
gullet  (esophagus)  into  the  stomach.  The  only  modi- 
fications it  has  suffered  up  to  this  point  are  its  reduction 
•to  a  finer  condition  and  a  possible  action  of  the  mouth 
ferment  upon  the  starch.  After  the  food  is  swallowed, 
changes  of  another  kind  begin  sooner  or  later. 

Before  considering  gastric  digestion  from  a  chemical 
point  of  view,  we  should  become  acquainted  with  the 
widely  differing  structure  of  the  stomachs  of  the  various 
farm  animals.  Those  of  the  ox  and  horse  are  greatly 
unlike.  The  stomach  of  the  ox,  and  of  all  other  rumi- 
nants, consists  of  four  divisions  or  sacs,  whereas  with 
the  horse  and  pig  it  is  made  up  of  a  single  sac. 

137.  The  ruminant  stomach. — The  ruminant  stomach 
is  really  quite  a  complicated  affair,  and  the  way  in  which 
it  disposes  of  the  food  is  understood  only  after  a  careful 
study  of  details.   It  has  four  divisions  or  sacs:  the  paunch, 
honeycomb,  many-plies,  and  rennet,  or  what  the  physi- 
ologist has  named  the  rumen,  reticulum,  omasum,  and 
abomasum.    With  the  ox  these  cavities  contain  on  the 
average  not  far  from  twenty-five  gallons,   about  nine- 
tenths  of  this  space  belonging  to  the  rumen  (Fig.  2). 

138.  Esophageal    groove. — A    gutter    or   canal    with 


100  THE  FEEDING   OF   ANIMALS 

an  incomplete  wall  runs  to  the  reticulum  and  omasum 
from  the  entrance  of  the  esophagus  into  the  rumen.  It 
communicates  both  with  the  rumen  and  reticulum.  The 
interior  of  this  canal  is  not  visible  in  its  passage  along  the 
inner  wall  of  the  reticulum  unless  the  lips  with  which  it 
is  provided  are  separated. 


FIG.  2.  Stomach  of  ox.  T,  rumen  or  paunch,  showing  attachment 
of  esophagus;  C,  reticulum  or  honeycomb;  O,  omasum  or  many-plies; 
A,  abomasum  or  rennet,  showing  attachment  of  small  intestine. 

139.  The  rumen. — The  food,  especially  in  its  first 
descent  from  the  mouth,  passes  at  first  mostly  into  the 
paunch  through  a  slit  in  the  gullet.  This  cavity,  as  stated, 
is  very  large,  and  it  may  properly  be  considered  as  an 
immense  reservoir  for  the  storage  of  the  bulky  materials 
which  the  ruminants  take  as  food.  It  is  divided  into 
four  sacs  by  constriction  in  its  walls  caused  by  strong 
muscular  bands.  As  is  the  case  with  the  entire  digestive 
canal,  the  walls  of  the  paunch  are  composed  of  three 
layers  of  tissue,  the  middle  one  being  a  very  thick  muscu- 
lar coat,  which  seems  necessary  to  produce  the  churning 
movement  of  the  large  mass  of  food.  The  inner  or  mucous 


THE  DIGESTION' OF  FOOD  101 

layer  is  covered  with  numerous  leaf-like  projections,  in 
which  the  blood  vessels  are  freely  distributed.  During 
its  stay  in  this  reservoir,  where  it  is  held  for  remastica- 
tion,  the  moist  food  becomes  thoroughy  softened  and 
besides  undergoes  a  variety  of  changes,  chiefly  those  due 
to  bacterial  ferments  which  probably  bring  about  the 
extensive  digestion  of  the  cellulose,  estimated  at  from  60 
to  70  per  cent.  These  fermentations  are  attended  by  an 
evolution  of  gases,  which  under  ordinary  conditions  are 
absorbed  into  the  blood  current.  It  may  be  suggested 
that  hoven  and  the  puffing  up  of  the  paunch  of  a 
freshly-killed  bovine  are  due  to  the  partial  or  total  failure 
of  the  blood  to  take  up  these  gases.  Sometimes  unnatural 
and  dangerous  fermentations  set  in,  induced  often  by  the 
consumption  in  the  spring  of  a  large  quantity  of  easily 
fermentable  food  such  as  green  clover.  This  causes  hoven, 
and  unless  the  gas  pressure  is  at  once  relieved  by  an 
opening  the  animal  often  dies,  due  sometimes  to  the 
bursting  of  the  rumen.  Some  authorities  claim  that 
proteolytic  and  amylolytic  changes  occur  in  the  rumen 
brought  about  not  by  enzyms  secreted  by  the  rumen  but 
by  those  contained  in  the  food. 

140.  The  reticulum. — A  portion  of  the  food  reaches 
the  reticulum  either  through  the  esophageal  slit  when 
first  swallowed,  or  through  a  large  opening  between  the 
rumen  and  the  reticulum.  That  which  goes  directly  to  the 
reticulum  when  swallowed  is  mostly  fluid.  The  reticulum 
also  communicates  with  the  third  stomach  by  an  opening. 
This  is  the  smallest  division  of  the  stomach,  and  derives 
its  common  name  from  the  fact  that  its  interior  surface 
is  divided  by  ridges  of  the  mucous  membrane  into  cells 
which  bear  a  close  resemblance  to  a  honeycomb.  These 
cells,  which  are  several-sided  and  quite  deep,  appear  to 


102  THE  FEEDING  OF  ANIMALS 

be  a  "catch-all"  for  the  foreign  bodies  which  animals  are 
liable  to  swallow,  such  as  small  stones,  pins,  and  nails. 
The  contents  of  this  compartment  of  the  stomach  are  very 
watery,  and  by  being  forced  into  the  esophagus  and 
rumen  appears  to  aid  the  return  of  the  food  to  the  mouth, 
portion  by  portion,  for  remastication. 

141.  Rumination. — Rumination,  which  is  the  re-chew- 
ing of  food  previously  swallowed,  is  peculiar  to  bovines, 
sheep,  and  goats.   In  the  case  of  these  species,  the  masti- 
cation of  coarse  fodder  is  not  completed  before  it  is  swal- 
lowed the  first  time,  and  they  have  the  power  of  return- 
ing to  the  mouth  the  material  which  has  become  stored 
in  the  rumen  and  reticulum  in  order  that  it  may  be  more 
finely  ground.  This  is  what  is  termed  "chewing  the  cud." 
It  is  an  operation  which  greatly  aids  digestion  by  render- 
ing the  food  mass  finer  and  more  susceptible  to  the  action 
of  the  digestive  fluids.   Animals  fed  on  grain  alone  do  not 
ruminate.    They  "lose  their  cud,"  a  condition  popularly 
and  erroneously  supposed  to  be  fatal  to  the  animal's 
life.  The  bolus  or  "cud"  of  the  bovine  weighs  approxi- 
mately four  ounces  and  requires  for  its  mastication  not 
far  from  one  minute,  including  preparation,  transference 
to  the  mouth,  and  return.    It  is  essential  to  rumination 
that  the  supply  of  liquid  to  the  rumen  be  abundant,  to 
which  the  salivary  glands  contribute  a  large  share. 

142.  The    omasum. — After    remastication,    the    food 
does  not  return  wholly  to  the  first  and  second  stomachs, 
but  is  mostly  carried  along  the  esophageal  groove  to  the 
third  stomach,  the  omasum.   The  finer  portions  may  even 
do  this  when  first  swallowed.    The  omasum  is  a  cavity 
somewhat  larger  than  the  reticulum,  which  has  a  most 
curious  interior  structure.  It  is  filled  with  extensions  of  the 
mucous  membrane  in  the  form  of  leaves,  between  which 


THE  DIGESTION   OF  FOOD  103 

the  food  passes  in  thin  sheets,  an  arrangement  which 
seems  to  have  for  its  purpose  the  further  grinding  of  the 
food  so  that  when  it  finally  reaches  the  fourth  and  last 
compartment  it  is  in  a  very  finely  divided  condition  and 
is  thoroughly  prepared  for  the  action  of  the  juices  that 
are  subsequently  poured  upon  it. 

143.  The  abomasum. — It  is  at  the  last  stage  of  the 
journey  of  the  food  through  this  complicated  stomach 
that  it  is  submitted  to  the  true  gastric  digestion.    As  a 
matter  of  fact,  the  abomasum,  or  rennet,  is  regarded  as  the 
true  stomach,  the  other  three  sacs  being  considered  as 
enlargements  of  the  esophagus.    In  the  calf,  the  rennet  is 
only  partly  developed,  the  other  divisions  not  coming  into 
use  until  the  animal  takes  coarse  foods  in  considerable 
quantity.    The  fourth  stomach  is  larger  than  either  the 
second  or  third.    It  receives  directly  from  the  omasum 
the  finely  divided  food,  upon  which  it  pours  the  gastric 
juice,  a  liquid  that  is  secreted  in  large  quantity  by  glands 
located  in  its  inner  or  mucous  membrane. 

144.  The  gastric  juice. — This  juice,  like  all  the  diges- 
tive fluids,  is  mostly  water,  the  proportion  being  between 
ninety-eight  and  ninety-nine  parts  to  less  than  two  parts 
of*  various  compounds.   The  latter  consist  of  ferments,  a 
certain  amount  of  free  hydrochloric  acid  and  a  variety  of 
mineral  compounds,  prominent  among  which  are  calcium 
and  magnesium  phosphates   and   the   chlorides  of  the 
alkalies,  sodium  chloride  being  especially  abundant. 

145.  Artificial    digestion. — Especial    interest   pertains 
to  the  ferments  of  the  gastric  juice,  one  of  which,  in  con- 
nection with  free  hydrochloric  acid,  causes  a  most  impor- 
tant change  in  the  proteins  of  the  food  by  reducing  them 
through  hydrolytic  and  other  cleavages  to  soluble  forms. 
We  know  quite  definitely  about  this  action,  because  it  can 


104  THE  FEEDING  OF  ANIMALS 

be  very  successfully  produced  in  an  artificially  prepared 
liquid.  If  the  mucous  lining  of  a  pig's  stomach,  after 
carefully  cleaning  without  washing  with  water,  is  warmed 
for  some  hours  in  a  very  dilute  solution  of  hydrochloric 
acid,  an  extract  is  obtained  which  has  the  power  of  dis- 
solving lean  meat,  wheat  gluten,  and  other  proteins.  The 
active  agent  in  causing  this  solution  is  pepsin,  an  unor- 
ganized ferment  or  enzym  (see  Par.  128)  which  is  present 
in  the  gastric  fluid  of  all  animals. 

146.  Changes    in    stomach    digestion. — This    juice 
changes  proteins  to  peptones,  bodies  soluble  and  diffusible. 
The  change  to  peptones  is  not  a  single  step,  for  the  pro- 
tein passes  through  successive  stages  as  acid  proteins  and 
proteoses  before  it  reaches  the  peptone  form.    This  is 
largely  what  may  be  styled  progressive  hydrolysis.    An- 
other ferment  present  in  the  gastric  juice  is  the  one  which 
gives  to  rennet  its  value  as  a  means  of  coagulating  the 
casein  of  milk  in  cheese-making,  and  is  called  rennin.  The 
action  of  this  latter  body  is  especially  prominent  in  the 
stomach  of  the  calf  when  fed  exclusively  on  milk,  and  it 
is  the  calf's  active  stomach,  the  fourth  in  the  mature 
animal,  which  is  the  source  of  commercial  rennet.  Lipase, 
an  enzym  that  acts  in  the  fats,  is  also  possibly  present 
in  the  gastric  juice  of  herbivorse.    (See  Par.  129.) 

147.  Hydrochloric  acid  essential  in  stomach  diges- 
tion.— The  free  hydrochloric  acid  in  the  gastric  juice  is 
also  actively  concerned  in  protein  digestion.    It  is  found 
that  a  solution  of  pepsin  has  a  limited  effect  in  the  absence 
of  free  acid,  for  when,  during  artificial  digestion,  the 
supply  of  this  acid  is  used  up,  it  must  be  renewed  or 
digestion  is  checked. 

148.  The  stomachs  of  the  horse  and  pig. — These  con- 
sist of  a  single  sac,  so  that  digestion  with  these  animals  is 


THE  DIGESTION  OF  FOOD 


105 


a  much  simpler  matter  mechanically  than  with  ruminants. 
Chemically,  the  results  are  essentially  similar,  i.  e.,  the 
protein  is  in  part  changed  to  peptones.  The  food,  after 
being  swallowed,  is  not  returned  to  the  mouth,  but  is 
very  soon  brought  under  the 
action  of  the  gastric  juice  with- 
out so  long-continued  preliminary 
preparation  by  remastication  and 
trituration.  For  this  reason  the 
horse  fails  to  digest  coarse  fodders 
so  completely  as  the  ox  does. 
Besides,  the  stomachs  of  the  horse 
and  pig  are  too  small  to  admit  of 
so  large  an  ingestion  of  hay  or 
similar  material,  as  is  the  case 
with  ruminants  of  similar  size.  In 
all  species,  however,  the  chemical 
result  of  stomach  digestion  is 
essentially  the  same,  i.  e.,  the  protein  is  in  part  changed 
to  peptones.  (Fig.  3.) 


FIG.  3.  Stomach  of 
horse.  B,  esophageal  at- 
tachment; A,  pyloric  end 
of  stomach,  with  beginning 
of  small  intestine. 


THE   INTESTINES 

The  most  extended  portion  of  the  alimentary  canal, 
though  not  the  most  capacious  in  all  cases,  is  the  intes- 
tines. They  consist  of  a  tube  differing  in  size  in  its  vari- 
ous portions,  which  begins  with  the  stomach  and  ends 
with  the  anus. 

149.  Form  and  length  of  intestines. — This  tube  is 
not  a  straight  passage  between  the  points  named,  but 
presents  curves  and  folds,  so  that  when  straightened  out 
it  appears  surprisingly  long.  Its  average  length  with  the 
ox  is  given  as  187  feet,  sheep  107  feet,  horse  98  feet,  and 


106  THE  FEEDING  OF  ANIMALS 

hog  77  feet,  lengths  which  are  from  twelve  to  twenty-six 
times  that  of  the  body  of  the  animal.  The  intestines  are 
divided  into  large  and  small,  the  latter  being  from  three 
to  four  times  as  long  as  the  former. 

150.  Food  in  the  small  intestine. — When   the   food 
leaves  the  stomach,  it  enters  the  small  intestine.    At  this 
point  it  is  only  partially  digested.   The  fats  are  probably 
so  far  mostly  unchanged  and,  without  doubt,  the  larger 
proportion  of  the  proteins  and  carbohydrates  that  are 
susceptible  of  digestion  is  still  in  the  original  condition. 
Hardly  has  this  partially  dissolved  material  passed  into 
the  small  intestines  before  it  comes  in  contact  with  two 
new  liquids  which  are  poured   on   it  simultaneously  or 
nearly  so,  viz.,  the  bile  and  the  pancreatic  juice,  and  the 
changes  which  began  in  the  mouth  and  stomach,  with 
others  which  set  in  for  the  first  time,  proceed  vigorously. 

151.  The  bile.— The  bile  has  its  source  in  the  liver.   It 
is  a  secretion  of  this  organ,  and  after  elaboration  a  reserve 
is  stored,  until  required,  in  a  small  sac  attached  to  the 
liver  which  is  called  the  "gall  bladder."   Gall  is  conveyed 
to  the  intestines  through  a  duct  opening  very  near  the 
orifice  leading  out  of  the  stomach.   The  rate  of  secretion 
of  bile,  according  to  experiments  by  Colin,  is  as  follows: 
Horse,  eight  to  ten  ounces  an  hour;  ox,  three  to  four 
ounces  an   hour;    sheep,  one-fourth   to   five  ounces   an 
hour;  pig,  two  to  five  ounces  an  hour.   The  secretion  and 
flow  of  bile  are  continuous  but  the  flow  is  not  uniform. 
Bile  is  a  liquid  varying  when  fresh  from  a  golden  red  color 
in  man  to  a  grass-green  or  olive-green  in  certain  herbiv- 
orous animals.    It  is  alkaline,  bitter  to  the  taste  and 
without  odor.    The  specific  and  characteristic  constitu- 
ents of  the  bile  are  two  acids,  glycocholic  and  tauro- 
cholic,  that  are  combined  with  sodium  and  are  associated 


THE  DIGESTION  OF  FOOD  107 

with  two  coloring  matters,  bilirubin  and  biliverdin. 
Numerous  other  compounds  are  present  in  very  small 
proportions,  such  as  fats,  soaps,  and  mineral  compounds, 
but  they  appear  to  have  no  important  relation  to  diges- 
tion. If  any  ferment  is  present  at  all,  it  is  only  as  a  trace, 
and  therefore  the  bile  is  incapable  of  effecting  decomposi- 
tions of  the  proteins  and  carbohydrates,  such  as  occur  in 
the  mouth  and  stomach. 

152.  Function  of  bile. — Nevertheless,  this  liquid  must 
be  regarded  as  having  an  important  function,  which  it 
exerts  in  two  ways,  (1)  by  preparing  the  chyme  (partially 
digested  food  from  the  stomach)  for  the  action  of  the 
pancreatic  juice  and  (2)  it  acts  in  conjunction  with  the 
pancreatic  juice  in  preparing  the  fats  for  absorption. 

Pepsin,  the  stomach  ferment,  acts  upon  proteins  only 
in  an  acid  medium.  The  opposite  is  true  of  the  ferments 
which  the  food  meets  in  the  intestines,  for  these  require 
an  alkaline  medium.  The  bile  neutralizes  the  acidity  of 
the  chyme,  and  so  prepares  the  way  for  the  pancreatic 
juice  to  do  its  work.  It  is  shown  that  when  the  entrance 
of  the  bile  into  the  intestines  is  prevented  the  fat  of  the 
food  largely  passes  off  in  the  feces. 

Bile  has  very  little,  if  any,  direct  digestive  action,  but 
it  may  be  said  to  cooperate  with  the  pancreatic  juice 
in  accomplishing  the  digestion  of  fats.  It  emulsifies  fats, 
especially  in  the  presence  of  the  pancreatic  juice.  When 
the  fats  are  split  by  a  ferment  in  the  pancreatic  juice  we 
get  as  a  result  fatty  acids  which  combine  with  the  alka- 
lies present  to  form  soaps.  Both  the  fatty  acids  and  the 
soaps  are  dissolved  by  the  bile.  In  this  way  the  fats  are 
prepared  for  absorption.  In  experiments  by  Vail  on  dogs, 
cutting  off  the  supply  of  bile  reduced  the  absorption  of  fat 
from  99  to  40  per  cent. 


108  THE  FEEDING   OF   ANIMALS 

It  has  been  asserted  that  the  bile  has  more  or  less 
antiseptic  influence  and  so  prevents  the  intestinal  con- 
tents from  undergoing  putrefactive  fermentation.  A 
more  rational  explanation  is  that  because  the  bile  acts  as 
a  natural  purgative  the  food  residues  pass  promptly  out 
of  the  intestinal  tract  before  the  putrefactive  fermenta- 
tions set  in  which  would  occur  in  the  absence  of  bile. 

153.  The   pancreatic    juice. — This   secretion  has  the 
most  comprehensive  action  on  the  food  nutrients  of  any 
one  of  the  intestinal  liquids.  It  originates  in  the  pancreas 
(sweetbread).    Its  flow  is  intermittent,  being  induced  by 
the  reaction  especially  of  the  acids  in  the  partially  digested 
foods   from   the   stomach.    The   amount   secreted   and 
its  composition  appear  to  change  with  the  kind  of  food. 
It  contains  with  the  horse  about  98.2  per  cent  of  water 
and  1.8  per  cent  of  solid  matter.   With  the  dog  the  per- 
centage of  water  is  about  90.  This  secretion  acts  upon  all 
classes  of  nutrients,  as  it  contains  a  variety  of  ferments 
greatly  unlike  in  function. 

154.  The  enzyms  of  the  pancreatic  juice. — The  three 
enzyms  present  in  the  pancreas  secretion  are:  a  protein- 
splitting  enzym,   trypsin  (or   its  progenitor),  a  starch- 
splitting  enzym,  amylopsin,  and  a  fat-splitting  enzym, 
steapsin.   Trypsin,  like  pepsin,  hydrolizes  the  protein  by 
progressive   stages   to   proteoses,    then    peptones,    after 
which,  in  conjuction  with  erepsin  (see  later),  breaks  the 
peptones  into  simpler  bodies  known  as  the  amino  acids. 
(See  Par.  84.)    Trypsin  acts  in  neutral  or  in  alkaline  solu- 
tions, a  free  mineral  acid  like  hydrochloric  completely 
stopping  its  operation.   Organic  acids,  like  lactic,  do  not 
seem  to  have  this  effect. 

155.  Steapsin. — The  pancreatic  secretion  acts  vigor- 
ously on  fats,  not  only  splitting  them  into  fatty  acids  and 


THE  DIGESTION  OF  FOOD  109 

glycerin,  but,  in  conjunction  with  the  bile,  also  effects 
their  emulsification,  this  latter  result  being  aided,  doubt- 
less, by  the  soaps  which  are  formed  from  a  union  of  the 
fatty  acids  and  the  alkaline  bases  (mostly  sodium)  in 
the  bile.  The  cleavage  of  the  fats  is  due  to  an  enzym  to 
which  the  name  of  steapsin  is  given,  also  called  "lipase." 
(See  Par.  128.) 

156.  Amylopsin. — We  have  seen  that  starch  is  acted 
upon  to  a  small  extent  by  the  saliva,  and  that  this  action 
is  not  prolonged  in  the  stomach  beyond  the  time  when  the 
stomach  contents  become  fully  acidified.    Starch  diges- 
tion is  therefore  carried   on  mainly  in  the  intestines, 
chiefly,  if  not  wholly,  by  a  diastatic  ferment  in  the  pan- 
creatic juice  which  has  the  power  of  hydrolyzing  the 
starch  mostly  into  maltose.    This  pancreatic  diastase, 
called  amylopsin  by  some  authors,  is  not  found  in  the 
digestive  tract  of  young  animals  as  abundantly  during 
the  period  of  milk-feeding  as  after  vegetable  foods  are 
taken,  for  milk  does  not  require  the  action  of  a  diastatic 
ferment.    The  presence  of  bile  is  very  favorable  to  the 
action  of  amylopsin.   (See  Par.  128.) 

157.  Intestinal  juices. — Mention  has  been  made  of 
juices  that  are  secreted  by  small  glands  distributed  in 
the  walls  of  the  small  intestine.    These  are  quite  impor- 
tant factors  in  digestion,  as  they  supplement  the  action 
of  the  ferments  of  the  pancreatic  juice.   It  appears  to  be 
shown  that  an  enzym,  erepsin,  is  found  in  these  juices 
that  is  unable  to  act  upon  any  of  the  native  proteins 
except  casein,  but  has  the  power  of  decomposing  proteoses 
and  peptones  into  simpler  compounds,  particularly  the 
amino-acids.   These  secretions  contain,  also,  the  ferments 
that  hydrolize  sucrose,  maltose,  and  lactose  into  dextrose. 
It  is  held  also  that  trypsin  does  not  exist  as  such  in  the 


110  THE  FEEDING  OF  ANIMALS 

pancreatic  juice  when  poured  into  the  small  intestine,  but 
that  this  enzym  is  formed  from  a  mother  substance  in  the 
pancreatic  juice  (trypsinogen)  after  it  comes  in  contact 
with  the  intestinal  juice,  this  result  being  accomplished 
through  the  action  of  a  body  probably  secreted  from 
the  intestinal  walls  and  called  by  Pawlow  "enterokinase." 
(See  Par.  154.) 

158.  Intestinal  bacteria. — So  far,   in   presenting   the 
relation  of  ferments  to  digestion,  only  the  unorganized 
ferments  or  enzyms  have  been  considered.    While  these 
are    chiefly    concerned    in    normal    digestion,    organized 
ferments   are   present   throughout   the   entire   intestinal 
canal  and  play  a  part  in  food  changes.    They  are  very 
abundant  and  active  in  the  rumen  and  large  intestine. 
They  act  upon  the  proteins,  causing  putrefaction,  dissolve 
cellulose,  and  cause  a  decomposition  of  the  carbohydrates. 
The  products  of  these  fermentations  include,  among  other 
compounds,  indol  and  skatol,  which  have  the  character- 
istic fecal  odor,  volatile  fatty  acids,  and  gases,  some  of 
which  are  carbon  dioxid,  hydrogen,  marsh  gas  and  hydro- 
gen sulfide:'  -The  evolution  of  these  gases  appears  to  occur 
constantly  and  normally  with  farm  animals,  particularly 
the  bovines,  the  quantity  depending  somewhat  upon  the 
kind  of  food.    (See  Par.  127.) 

159.  Effects  of  intestinal  fermentations. — Under  cer- 
tain conditions,  fermentations  of  this  character,  which 
are  in  part  normal  and  may  be  beneficial,  proceed  so 
far  as  to  be  deleterious.   Gorging  with  a  very  succulent 
food,  such  as  immature   clover,  after  a  period  of  dry 
foods,    or   anything   which   retards   digestion,    such   as 
imperfect  mastication,  excessive  eating,  and  failure  of  the 
organs  secreting  the  digestive  fluids  to  supply  these  fluids 
in  sufficient  abundance,  give  these  bacteria  a  better  oppor- 


THE  DIGESTION  OF  FOOD  111 

tunity  to  act  on  the  food  residues,  and  increase  their 
effect.  Recent  results  appear  to  indicate  that  the  syn- 
thetic activities  of  intestinal  bacteria  may  be  a  matter  of 
some  importance  in  the  utilization  of  amides  (Par.  273). 

160.  Stimuli  to  digestion. — The  gastric  juice  is  not 
constantly  poured  into  the  stomach  to  accumulate  there, 
but  is  secreted  as  it  is  needed  under  the  influence  of  cer- 
tain stimuli.   These  stimuli  may  be  classed  as  psychic  and 
chemical.   Appetizing  odors  when  there  is  a  strong  desire 
to  eat,  and  the  agreeable  taste  of  food  in  the  mouth  of  a 
hungry    person    are    important    psychic    or    "nervous" 
influences  that  promote  gastric  digestion  through  stimu- 
lating the  secretion  of  an  adequate  supply  of  the  digest- 
ing fluid.    Other  stimuli  that  may  be  called  chemical 
result  from  the  indirect  reaction  of  certain  substances 
upon  the  secretory  glands.    With  man,  meat  extracts, 
proteoses,  acids,  sugars,  alcohol,  and  condiments  seem  to 
be  effective  in  this  way.    This  stimulus  comes  later  than 
the  psychic,  but  is  more  prolonged. 

161.  Secretins. — The  more  recent  researches  indicate 
that  the  first  products  of  digestion,  reacting  on  the  inner 
membranes  of  the  stomach  and  duodenum,  cause  the 
formation  of  substances  called  secretins  that  belong  to 
the  general  class  of  excitants  known  as  hormones,  which, 
carried  by  the  blood  stream  to  the  cells  of  secretory  glands, 
excite  the  secretion  of  the  digestive  juices.   It  now  seems 
possible  that  sometime  we  shall  have  a  definite  dietetic 
method  of  influencing  human  digestion,  at  least,  other  than 
a  medicinal,  for  it  appears  that  certain  food  compounds 
may  stimulate  and  others  retard  the  activity  of  digestion. 

162.  The  psychic  factor. — The  psychic  factor  is  no 
less  important.   This  being  so,  it  is  seen  how  necessary  it 
is  that  eating  shall  be  pleasurable.    Satisfaction  with  the 


112  THE  FEEDING  OF   ANIMALS 

diet,  even  with  an  animal,  undoubtedly  is  a  determina- 
tive element  in  good  digestion.  Moreover,  condiment al 
stimulation  is  a  poor  makeshift  for  the  effect  of  a  healthy 
liking  for  food.  There  are  good  reasons  for  believing  that 
psychic  stimulation  is  an  important  factor  in  digestion 
with  farm  animals.  Whether  the  theory  of  chemical 
stimuli  applies  to  this  class  of  animals  is  less  certain. 

163.  Digestion  of  food  as  a  whole. — From  what  has 
preceded  we  learn  that  several  liquids  and  certain  organ- 
isms participate  in  producing  the  complex  changes  that 
food  undergoes  during  digestion.    Some  of  these  liquids 
have  certain  common  functions,  as,  for  instance,  pro- 
teins are  acted  upon  both  by  the  gastric  and  pancreatic 
juices.    Moreover,  the  various  digesting  fluids  appear  to 
act  cooperatively.    This  is  made  plain  by  following  the 
course  of  the  food  changes. 

164.  Stomach  digestion. — After  the  food  has  remained 
in  the  stomach  for  a  certain  period  of  time,  it  is  gradually 
discharged  into  the  small  intestine,  the  rate  of  discharge 
varying  with  the  kind  of  food,  that  is,  with  the  prompt- 
ness and  rapidity  of  digestion,  which  differs  with  different 
foods.   The  progress  made  up  to  this  point  in  food  trans- 
ference, so  far  as  we  have  definite  knowledge,  is  chiefly  the 
cleavage  of  the  proteins  into  various  stages  of  hydrolysis, 
the  resulting  bodies  being  proteoses  and  peptones.    All 
proteins  appear  to  be  acted  on  in  the  stomach,  but  to 
different  degrees  and  probably  at  different  rates.   Starch, 
already  somewhat  dissolved  by  the  saliva,  is  not  further 
acted  upon  by  the  stomach  enzyms,  neither  are  the  solid 
and  liquid  fats  affected  to  any  material  extent.    Simple 
sugars  are  not  acted  upon  by  the  gastric  juice,  but  it  seems 
possible  that  the  di-sugars  may  be  split  into  simple  cnes 
by  the  hydrochloric  acid. 


THE  DIGESTION  OF  FOOD  113 

165.  Digestion  in  intestines. — It  appears,  then,  that  in 
the  intestines  protein  digestion  must  be  completed  with 
the  cleavage  of  peptones  into  the  simpler  amino  acids, 
the  larger  part  of  the  starch  transformed  to  sugar  and  the 
digestion  of  the  fats  wholly  accomplished  or  mainly  so. 
As  a  matter  of  fact,  the  partial  solution  in  the  stomach  of 
the  proteins  and  the  swelling  of  the  undissolved  part  to  a 
gelatinous  mass  may  be  considered  as  a  preparation  of  the 
food  for  intestinal  digestion,  for  through  these  changes 
the  proteins  present  a  larger  surface  to  the  attack  of 
trypsin  and  other  intestinal  enzyms  and  digestion  pro- 
ceeds more  promptly  than  would  be  the  case  with  the 
freshly  ingested  food.    Moreover,  the  compounds  in  the 
chyme,  especially  the  acid,  indirectly  react  on  the  liver 
and  pancreas,  and  cause  an  abundant  flow  of  digestive 
fluids  from  these  glands. 

166.  Digestive  fluids  act  together. — As  soon  as  the 
chyme  mixes  with  the  bile  and  pancreatic  juice,  the  mass 
is  changed  from  an  acid  to  an  alkaline  condition.    This 
seems  to  be  essential  to  the  effective  operation  of  the 
pancreatic   ferments.     While   the   pancreatic   juice   will 
carry  on  digestion  by  itself,  this  is  not  satisfactory  in  the 
absence  of  bile,  one  reason  for  this  being  that  when  the 
latter  is  not  permitted  to  enter  the  small  intestine,  the 
digestion  of  fats  is  very  imperfect.   It  seems  essential  that 
these  two  liquids  act  together.   The  bile  aids  in  rendering 
the  digesting  mass  alkaline,  contributes  to  the  formation 
and  solution  of  the  fatty  acids  and  soaps,  and  in  these 
ways  promotes  the  activity  of  the  pancreas  enzyms. 

167.  Action  of  intestinal  juices. — The  juices  that  flow 
from  the  small  glands  in  the  intestinal  walls  appear  essen- 
tially to    supplement   the  work  of   the  bile   and   pan- 
creatic juice.    In  the  first  place,  they  probably  contain  a 


114  THE  FEEDING   OF  ANIMALS 

substance  that  activates  the  mother  substance  of  tryp- 
sin;  in  the  second  place,  they  aid  in  splitting  the  pep- 
tones into  simpler  bodies,  and,  lastly,  they  convert  cer- 
tain sugars  into  the  final  form  (dextrose)  in  which  they 
are  absorbed  into  the  blood  circulation. 

168.  Summary  of  changes  in  digestion. — If  we  con- 
sider the  digestion  of  the  food  compounds  by  classes,  the 
following  is  a  summary  of  the  ways  in  which  they  are 
acted  upon:  pepsin,  trypsin,  and  erepsin  secreted  by  the 
stomach,  pancreas,  and  intestinal  glands  act  on  the  pro- 
teins; ptyalin  in  the  saliva,  amylopsin  from  the  pancreas, 
and  lactase,  maltase,  and  sucrase  in  intestinal  secretions 
act  on  the  carbohydrates,  and  the  fats  are  acted  on 
mainly  by  the  lipase  of  the  pancreatic  juice. 

The  bacteria  are  not  surely  known  to  have  necessary 
specific  digestive  functions,  unless  it  be  their  solvent  action 
on  the  cellulose. 

It  should  be  observed  that  the  above  is  a  presenta- 
tion of  the  general  scheme  of  digestion,  and  takes  no 
account  of  differences  between  the  various  species  of 
farm  animals  of  which  our  knowledge  is  incomplete. 

ABSORPTION   OF   FOOD 

From  the  time  the  food  enters  the  stomach,  during 
nearly  its  entire  course  along  the  alimentary  canal,  there 
is  a  constant  production  of  soluble  compounds,  which 
progressively  disappear  into  other  channels,  so  that  when 
the  anus  is  reached  only  a  portion  of  the  original  dry 
matter  is  found  in  the  residue.  In  some  way,  not  wholly 
explainable  in  all  its  details,  the  digested  food  has  been 
absorbed  and  received  into  vessels  through  which  it  is 
distributed  to  the  various  parts  of  the  body. 


THE  DIGESTION  OF  FOOD 


115 


169.  Function  of  lacteals  and  blood  vessels  in  absorp- 
tion (Figs.  4,  5). — A  merely  casual  observation  shows  us 
that  the  inner  surface  of  the  walls  of  the  small  intestine  is 
covered  by  numerous  projections,  called  villi.  In  these  are 
imbedded  the  minute  branches  of  two  systems  of  vessels, 


MXJCOU9 
COAT 


LLAYER  OF  CIRCULAR  FIBRES' 
^YER  OF  LONGITUDINAL  FIBRES' 


FIG.  4.   Cross-section  of  mucous  membrane  of  small  intestine  of  man, 
showing  capillaries  and  lacteals.    (Gerrish.) 

the  lacteals,  belonging  to  the  so-called  lymphatic  system, 
and  the  capillaries,  which  are  minute  branches  of  the 
blood  system.  The  lacteal  is  in  the  center  of  each  villus 
and  this  is  surrounded  by  a  network  of  capillaries.  The 
lymphatic  vessels  lead  to  a  main  tube  or  reservoir,  the 
thoracic  duct,  which  extends  along  the  spinal  column 


116 


THE  FEEDING   OF  ANIMALS 


and  finally  enters  one  of  the  main  blood  vessels.  Any 
material,  therefore  taken  up  by  the  lacteals  ultimately 
reaches  the  blood.  The  capillaries  all  converge  to  a  larger 
blood  vessel,  known  as  the  portal  vein,  which  enters  the 
liver,  transferring  to  that  organ  whatever  material  the 
capillaries  have  absorbed. 

170.  Manner   of   food   absorption. — The   manner   in 
which  the  soluble  food  is  absorbed  has  been  explained  in 

part  on  common  physical  grounds. 
When  two  solutions  of  different  densi- 
ties, containing  diffusible  compounds, 
are  separated  by  a  permeable  mem- 
brane, diffusion  through  this  membrane 
from  the  denser  to  the  lighter  liquid 
will  always  occur.  Such  a  condition 
as  this  prevails  in  the  intestines,  we 
may  believe.  The  intestinal  solution, 
the  denser  one,  is  separated  from  a 
less  concentrated  liquid,  the  blood, 
which  is  constantly  flowing  on  the 
other  side  of  a  thin  dividing  mem- 
brane. Under  these  conditions  there 
occurs  the  passage  into  the  blood  of 
certain  parts  of  the  digested  food.  It 
is  held  that  in  this  way  water,  soluble 
mineral  salts,  and  sugar  pass  directly 
into  the  blood  vessels,  chiefly  from 
the  small  intestine. 

171.  Changes  in  the  walls  of  the  intestinal  tract. — 
In  the  absorption  of  peptones  and  fats,  at  least,  forces  are 
encountered  other  than  the  osmotic  transference  of  sub- 
stances in  solution,  the  operation  of  which  is  still  more  or 
less  unexplained. 


FIG.  5.  Intestinal 
villas,  showing:  a, 
epithelium;  b,  capil- 
laries; c,  lacteal  ves- 
sels. 


THE  DIGESTION   OF  FOOD  117 

The  ingested  proteins  are  changed  in  the  stomach  and 
intestines  to  peptones,  and  in  part,  perhaps  mainly,  to 
amino  acids  resulting  from  the  cleavage  of  peptones.  The 
fats  are  split  partly,  or  entirely,  into  fatty  acids  and  glyc- 
erin, with  the  subsequent  formation  of  soaps  by  the  union 
of  the  free  acids  with  alkaline  bases.  It  has  been  held  that 
in  the  passage  of  these  new  compounds  through  the  walls 
of  the  intestine  changes  occur  of  a  synthetical  character, 
with  a  partial  or  total  reconstruction  of  the  proteins  and 
fats  into  forms  similar  to  those  in  the  ingested  food.  This 
view  as  to  the  proteins  has  been  modified  somewhat  by 
the  demonstration  of  the  existence  of  amino  acids  in  the 
blood  showing  that,  if  a  synthesis  of  proteins  occurs  in  the 
intestinal  walls,  it  is  at  least  not  complete.  Amino 
acids  may  exist  in  the  blood  even  if  synthesis  occurs  in 
the  intestinal  walls.  The  rebuilding  of  fats  and  their 
transference  into  the  lacteals  is  regarded  as  being 
accomplished  through  the  activity  of  cells  lying  in  the 
mucous  lining  of  the  intestine.  This  seems  to  be  proven. 
It  seems,  then,  that  the  vital  forces  residing  in  these 
cells  probably  play  a  part  in  the  transfer  of  the  nutrients 
into  the  blood  circulation,  and  that  this  absorption 
can  not  be  explained  wholly  on  the  basis  of  osmotic 
pressure. 

172.  Place  of  maximum  absorption  of  food. — Absorp- 
tion of  digested  food  takes  place  to  a  limited  extent 
from  the  stomach  of  man  and  the  dog,  but  not  from  the 
stomach  of  the  herbivora.  The  main  transference  of  the 
products  of  digestion  into  the  blood  is  from  the  intestines, 
particularly  the  small  intestine.  Much  of  the  water  that 
passes  into  the  large  intestine  is  absorbed  there,  together 
with  the  products  of  digestion  not  already  absorbed  and 
those  products  that  result  from  bacterial  action. 


118  THE  FEEDING  OF  ANIMALS 

THE   FECES 

The  soluble  and  insoluble  portions  of  the  intestinal 
contents  become  separated  gradually,  and  the  undissolved 
part  arrives  finally  at  the  last  stage  of  its  journey  along 
the  alimentary  canal,  and  is  expelled  as  the  solid  excre- 
ment, or  feces. 

173.  Constituents  of  feces. — The  feces  is  made  up  of 
the  undigested  food,  residues  from  the  bile  and  other 
digestive  juices,  mucus,  and  more  or  less  of  the  epithelial 
cells  which  have  become  detached  from  the  walls  of  the 
stomach  and  intestines.    Dead  and  living  bacteria  also 
appear  to  constitute  a  material  portion  of  the  fecal  mat- 
ter.   These  organisms  are  not  taken  in  with  the  food  to 
any  great  extent,  but  are  the  result  of  their  continuous 
growth  in  the  digestive  tract.    Small  quantities  of  fer- 
mentation products,  particularly  indol  and  skatol,  are 
present,  which  give  to  the  feces  its  offensive  odor.    The 
incidental  or  .waste  products  may  properly  be  considered 
as  belonging  to  the  wear  and  tear  of  digestion. 

174.  The   feces   not   wholly   undigested   food. — The 
ordinary  conception  of  the  fecal  residue  is  that  it  is  only 
the  part  of  the  food  that  has  resisted  the  action  of  the 
digestive  fluids,  but  in  fact  it  is  much  more  than  that.  Not 
only  does  it  include  the  various  waste  products  previ- 
ously referred  to,  but  also  compounds  that  have  been 
absorbed  into  the  blood  circulation  and  returned  to  the 
alimentary  canal  for  excretion.    It  has  been  shown,  for 
instance,  that  when  a   phosphorus   compound    was  in- 
jected subcutaneously  into  a  sheep,  the  phosphorus  was 
excreted  in  the  feces  in  another  combination.    It  is  also 
proven  that  mineral  compounds  absorbed  from  the  intes- 
tinal tract  may  afterward  appear  in  the  feces. 


THE  DIGESTION  OF  FOOD  119 

The  physical  condition  of  the  feces  is  characteristic 
with  each  species  of  animals,  the  differences  in  consistency 
being  due  largely  to  variations  in  the  amount  of  water 
present.  The  amount  of  water  in  feces  depends  more 
upon  the  character  of  the  food  eaten  than  upon  the 
amount  of  water  drunk. 

THE   RELATION    OF   THE  DIFFERENT    FOOD    COMPOUNDS  TO 
THE   DIGESTIVE    PROCESSES 

Numerous  digestion  experiments  with  a  large  variety 
of  foods  have  abundantly  established  the  fact  that  these 
materials  differ  greatly  in  their  solubility  in  the  digestive 
juices.  This  is  an  important  matter,  and  one  which  should 
be  well  understood,  for  we  must  consider  both  the  weight 
of  the  dry  matter  eaten  and  its  availability  in  determin- 
ing its  nutritive  value.  Variations  in  digestibility  are 
caused  primarily  by  variations  in  composition;  therefore, 
we  must  deal  fundamentally  with  the  susceptibility  of  the 
various  single  constituents  of  food  to  the  action  of  the 
several  digestive  ferments. 

In  this  connection,  we  need  to  pay  little  attention  to 
the  mineral  compounds  that  exist  in  the  inorganic  form 
in  the  food.  They  do  not  undergo  fermentative  changes 
in  the  way  that  the  carbon  compounds  do,  but  are  brought 
into  simple  solution  either  in  the  water  accompanying  the 
food,  or  in  the  juices  with  which  they  come  in  contact. 

175.  Digestibility  of  the  proteins. — As  has  been  noted, 
protein  is  a  mixture  of  nitrogenous  compounds.  The  gluten 
of  wheat  contains  at  least  five  of  these  bodies,  and  other 
seeds  as  many.  What  is  the  relative  susceptibility  of  these 
single  proteins  to  the  digestive  enzyms  either  as  to  rapid- 
ity or  completeness  of  change  does  not  appear  to  be  known. 


120  THE  FEEDING  OF  ANIMALS 

Some  proteins  are  pratically  all  digested  by  artificial 
methods,  and  probably  are  in  natural  digestion.  It  is 
known  definitely  that  protein  is  much  more  completely 
dissolved  from  some  foods  than  from  others.  That  of 
milk  and  meat  is  practically  all  digestible,  that  of  some 
grains  very  largely  so,  while  with  the  coarse  foods  quite  a 
large  proportion  escapes  solution.  Whether  this  is  due  to 
differences  in  the  characteristic  protein  compounds  of  the 
various  foods  is  not  quite  determined.  The  fact  that 
highly  fibrous  materials  show  the  lowest  proportion  of 
digestible  protein  suggests  as  an  explanation  that  the 
nitrogen  compounds  of  plant  tissue  are  so  protected  by  the 
cell-walls  that  they  escape  the  full  action  of  the  digestive 
juices.  It  is  certain,  however,  that  the  protein  in  plant 
tissue  is  less  fully  digested  than  that  from  milk  and 
meat  products. 

176.  Digestibility  of  the  carbohydrates. — In  the  case 
of  the  carbohydrates,  our  knowledge  of  the  relative  sus- 
ceptibility of  the  individual  compounds  to  enzym  action 
is  more  definite.    First  of  all,  the  necessary  modification 
of  the  sugars,  which  are  already  soluble,  is  slight,  and  they 
are  wholly  digested.    In  the  second  place,  we  have  learned 
in  two  ways  that  the  starches  are  wholly  hydrolized,  first 
by  submitting  them  in  an  artificial  way  to  the  action  of 
various  diastatic  ferments,  and,  second,  by  discovering 
a  complete  absence  of  starch  or  its  products  in  the  normal 
feces.   Under  normal  conditions  the  unprotected  starches, 
like  the  sugars,  are  completely  digestible. 

177.  Starches  unlike  in  rate  of  digestibility. — Digesti- 
bility must  be  considered,  however,  from  the  standpoints 
both  of  rapidity  and  of  completeness.    As  to  the  former 
factor,  starches  from  unlike  sources  exhibit  some  remark- 
able, differences.     Investigations    by    Stone,    who    sub- 


THE  DIGESTION   OF  FOOD  121 

mitted  a  number  of  these  bodies  to  the  action  of  several 
diastatic  ferments,  show  that  "this  variation  reaches  such 
a  degree  that,  under  precisely  the  same  conditions,  cer- 
tain of  the  starches  require  eighty  times  as  long  as  others 
for  complete  solution."  The  potato  starches  appear  to  be 
acted  upon  much  more  rapidly  than  those  from  the 
cereal  grains. 

178.  Digestibility  of  cellulose  and  gums. — Other  car- 
bohydrates, cellulose  and  hemicelluloses,  such  as  pento- 
sans,  galactan  mannan,  and  related  bodies,  show  great 
variations    in    digestibility    according    to    their    source, 
these  variations  ranging  in  observations  by  Swartz  from 
0  to  100  per  cent.   The  extent  to  which  these  latter  sub- 
stances  disappear  from  the   alimentary   canal   appears 
to  be  dependent  on  their  susceptibility  to  attack  by 
bacteria. 

179.  Digestibility  of  the  fats.— The  actual  extent  of 
the  digestion  and  absorption  of  the  fats  or  oils  is  also  not 
definitely  known.    If  we  were  to  accept  the  figures  given 
for   ether-extract  in  tables  of  digestion   coefficients  as 
applying  to  the  real  fats,  we  would  believe  that  their 
digestibility  varies  from  less  than  one-third  to  the  total 
amount.    It  is  unfortunately  true  that  these  coefficients 
mean  but  very  little.   The  ether-extract  from  some  foods 
is  only  partially  fat  or  oil,  as  we  have  seen,  and  the  inac- 
curacy of  a  digestion  trial  is  still  further  aggravated  by 
the  presence  in  the  feces  of  bile  residues  and  other  bodies 
which  are  soluble  in  ether,  so  that  the  difference  between 
the  ether-extract  in  the  ingested  food  and  that  in  the 
feces  does  not  give  accurate  information  as  to  what  has 
happened  to  the  actual  fats.    It  seems  very  probable  that 
pure  vegetable  fats  and  oils  and  all  mixed  animal  fats  are 
quite  completely  absorbed. 


122  THE  FEEDING  OF  ANIMALS 

The  foregoing  statements  make  it  plain  that  when  the 
general  composition  of  a  food  is  known,  it  is  possible  to 
predict  with  a  good  degree  of  certainty  whether  its  per- 
centage of  digestibility  is  high  or  low.  Feeding-stuffs 
with  a  high  percentage  of  starch  and  sugar  and  a  small 
percentage  of  fiber  have  a  relatively  high  digestibility,  as, 
for  instance,  corn  meal,  while  the  coarse  foods  like  timo- 
thy hay  and  straw,  with  a  high  proportion  of  gums  and 
fiber,  have  a  relatively  low  digestibility. 

FACTOBS  WHICH  MAY   INFLUENCE   DIGESTION 

Digestion  has  an  important  relation  to  the  nutritive 
efficiency  of  food  because  only  that  portion  of  the  food 
that  is  digested  and  absorbed  can  serve  the  purposes  of 
growth  and  the  maintenance  of  the  vital  functions. 

180.  Meaning  of  *  'digestibility." — In  discussing  the 
factors  that  may  influence  the  digestion  of  food,  it  is 
essential  to  understand  clearly  what  is  involved  in  the 
term  digestion  as  it  is  used  in  science  and  in  common 
speech.  This  term  includes  at  least  two  elements,  com- 
pleteness of  solution  of  the  food  nutrients  and  rate  of 
digestion.  The  figures  that  are  given  for  the  digestibil- 
ity of  various  cattle  foods  refer  to  the  completeness  or 
extent  to  which  the  food  is  dissolved  and  transferred  to 
the  circulation.  But  different  foods  from  which  come  the 
same  proportion  of  undigested  dry  matter  may  differ 
materially  in  the  rate  at  which  they  undergo  digestive 
changes,  and  in  this  sense  their  digestibility  is  unlike. 
The  ultimate  completeness  of  solution  in  the  digestive 
fluids  may  not  be  influenced  by  the  rate  at  which  the 
process  goes  on. 


CHAPTER  VIII 
CONDITIONS  INFLUENCING  DIGESTION 

THE  chemical  changes  and  other  phenomena  consti- 
tuting digestion,  which  have  been  described  as  occurring 
in  the  alimentary  canal,  are  practically  outside  the  con- 
trol of  the  one  who  feeds  the  animals.  They  proceed  in 
accordance  with  fixed  chemical  and  physiological  laws. 
It  is,  however,  within  the  power  of  the  feeder  to  so 
manipulate  the  food  or  vary  the  conditions  under  which 
it  is  fed  that  the  extent  or  completeness  of  digestion  is 
modified,  and  this  must  be  regarded  as  an  important 
matter  when  we  remember  that  only  the  digested  food 
is  useful. 

181.  Palatableness. — It  is  entirely  reasonable  to 
believe  that  a  thorough  relish  for  food  is  conducive  to 
good  digestion.  The  secretion  of  the  digestive  juices  is 
not  a  mechanical  process,  but  is  partly  under  the  control 
of  the  nervous  system.  With  man,  at  least,  the  enjoy- 
ment of  eating,  even  its  anticipation,  stimulates  the 
secretory  power  of  the  salivary  glands  and  those  in  the 
mucous  lining  of  the  stomach,  and  it  is  evident  that  this 
holds  true  with  animals.  Palatableness  is,  therefore,  an 
important  factor  in  successful  feeding,  for  it  tends  to  pro- 
mote a  state  of  vigorous  activity  on  the  part  of  the  diges- 
tive organs.  The  experienced  feeder  knows  well  the 
value  of  stimulating  the  appetite  of  his  animals  by  means 
of  attractive  mixtures.  An  agreeable  flavor  or  taste  adds 
nothing  to  the  energy  or  building-capacity  of  a  food,  but 

(123) 


124  THE  FEEDING  OF  ANIMALS 

it  does  tend  to  secure  a  thorough  appropriation  of  the 
nutrients  which  enter  the  alimentary  canal.  Without 
doubt,  the  success  of  one  feeder  as  compared  with  the 
failure  of  another  may  sometimes  be  due,  in  part,  to  a 
superior  manner  of  presenting  a  ration  to  the  animal's 
attention  and  to  manipulations  that  add  to  the  agreeable- 
ness  of  its  flavors.  (See  Par.  162.) 

182.  Influence  of  quantity  of  ration. — Early  experi- 
ments by  Wolff,  in  which  he  fed  larger  and  smaller  rations 
of  the  same  fodder  to  the  same  animals,  have  been  made 
the  authority  for  the  statement  that  a  full  ration  is  as 
completely  digested  as  a  scanty  one,  provided  the  former 
does  not  pass  the  normal  capacity  of  the  animal.  It  must 
be  said,  however,  that  the  testimony  concerning  this 
point  is  not  unanimous.  Since  Wolffs  experiments, 
Weiske,  in  feeding  oats  to  rabbits,  found  the  digestibil- 
ity to  be  inversely  as  the  quantity  of  food  taken.  In 
experiments  with  oxen,  by  G.  Kuhn,  at  Mockern,  when 
the  grain  ration  was  doubled  the  digestibility  of  the  malt 
sprouts  used  was  decreased  about  9  per  cent.  Results 
at  the  New  York  Experiment  Station  from  feeding  full 
and  half  rations  to  four  sheep  showed  uniformly  higher 
digestion  coefficients  with  the  smaller  ration,  the  differ- 
ences being  too  large  and  too  constant  to  be  considered 
accidental.  Other  experiments  give  varying  and  con- 
flicting figures-  If  we  assume  that  the  constituents  of 
feeding-stuffs  have  a  certain  fixed  solubility  in  the 
digestive  fluids,  then  within  reasonable  limits  the  amount 
of  food  should  have  no  effect  upon  the  proportions  of 
nutrients  digested,  but  such  an  assumption  cannot  safely 
be  made. 

Doubtless  no  single  statement  concerning  this  point 
will  be  found  applicable  to  all  animals  and  all  rations. 


CONDITIONS  INFLUENCING  DIGESTION  125 

Certainly,  over-feeding  may  lessen  the  extent  of  solution 
and  is  never  wise,  while  under-feeding  for  the  sake  of 
securing  a  maximum  digestibility  would  not  be  good 
practice.  It  is  reasonable  to  suppose,  however,  that  the 
relation  in  quantity  between  the  enzyms  and  the  food 
compounds  has  an  influence,  at  least,  upon  the  rapidity 
of  digestion;  and  indeed  investigations  by  Stone  very 
strongly  point  to  such  a  conclusion,  for  he  found  that  the 
rate  of  ferment  action  was  proportional  to  the  concentra- 
tion of  the  ferment  solution. 

183.  Effect  of  drying  fodders. — At  one  time  the  belief 
became  very  firmly  fixed  in  the  public  mind  that  curing 
a  fodder  causes  a  material  decrease  in  its  digestibility. 
Because  this  drying  is  often  carried  on  under  conditions 
that  admit  of  destructive  fermentations  or  of  a  loss  of 
the  finer  parts  of  the  plant,  this  view  is  probably  correct 
for  particular  cases;  but,  if  it  is  accomplished  promptly 
and  in  a  way  that  precludes  fermentation  or  loss  of  leaves, 
it  is  doubtful  if  curing  has  any  material  effect  upon 
digestibility. 

The  point  has  been  the  object  of  six  American  diges- 
tion experiments,  Hungarian  grass,  timothy,  pasture  grass, 
corn  fodder,  crimson  clover,  and  winter  vetch  being  the 
experimental  foods.  With  four  of  these,  slight  but  unim- 
portant differences  were  observed  in  favor  of  the  dried 
material,  while  the  reverse  was  decidedly  true  of  the 
crimson  clover  and  the  corn  fodder.  German  experiments 
show  in  a  majority  of  cases  greater  digestibility  for  the 
green  fodders.  It  seems  probable  that  in  general  prac- 
tice, because  of  greater  or  less  unavoidable  fermentations 
and  a  loss  of  the  finer  parts  of  the  plant,  dried  fodders  have 
a  somewhat  lower  rate  of  digestibility  than  the  original 
green  material,  a  fact  not  due  directly  to  drying,  but  to 


126  THE  FEEDING  OF  ANIMALS 

a  decrease,  either  of  the  more  soluble  compounds  or  of 
the  tender  tissues.    (See  Par.  306.) 

184.  Influence  of  the  conditions  and  methods  of 
preserving  fodders. — In  comparing  the  conditions  and 
methods  of  preserving  fodders  in  their  relation  to  digesti- 
bility, we  may  safely  rest  upon  the  general  statement 
that  when,  for  any  cause,  leaching  occurs  or  fermenta- 
tions set  in,  digestibility  is  depressed.  The  explanation 
of  this  statement  is  that  those  compounds  of  the  plant 
which  are  entirely  soluble  in  the  digestive  fluids,  notably 
the  sugars,  are  the  ones  wholly  or  partially  removed  or 
destroyed  by  leaching  or  fermentations,  while  the  more 
insoluble  bodies  remain  unaffected.  When,  therefore, 
hay  is  cured  under  adverse  conditions,  such  as  long-con- 
tinued rain,  digestibility  is  decreased,  and  the  same 
effect  is  inevitable  from  the  changes  which  occur  in  a 
fermenting  mass,  such  as  a  mow  of  wet  hay,  a  pile  of 
corn  stalks  or  the  contents  of  a  silo.  Experimental 
evidence  of  the  truth  of  these  statements  is  not  wanting. 
German  digestion  trials  with  alfalfa  and  esparsette, 
green,  carefully  dried,  cured  in  the  ordinary  way,  fer- 
mented after  partial  drying  and  as  silage,  show  a  grad- 
ually decreasing  digestibility  from  the  first  condition  to 
the  last.  A  single  American  experiment,  comparing  the 
same  fodder  both  green  and  as  silage,  gives  testimony  in 
the  same  direction.  On  the  other  hand,  field-cured  corn 
fodder,  according  to  nine  out  of  eleven  American  experi- 
ments, is  considerably  less  digestible  than  silage  coming 
from  the  same  source,  although  the  results  of  field  curing 
vary  greatly  according  to  the  conditions  of  exposure. 
Here  it  is  largely  a  question  of  the  relative  loss  by  fermen- 
tation in  the  two  cases,  and  it  is  to  be  expected  that  the 
outcome  would  not  be  wholly  one  way. 


CONDITIONS  INFLUENCING  DIGESTION  127 

185.  Influence  of  the  stage  of  growth  of  the  plant. — 

Another  generalization,  which  certainly  must  hold  good 
with  reference  to  the  digestibility  of  fodder  plants,  is  that 
any  conditions  of  development  which  favor  a  relatively 
large  proportion  of  the  more  soluble  carbohydrates,  viz., 
starches  and  sugars,  and  accompanied  by  a  minimum  of 
gums  and  fiber,  promote  a  high  rate  of  digestibility,  and 
reverse  conditions  produce  the  opposite  result.  It  is  well 
known  that,  in  general,  as  the  meadow  grasses  mature 
the  relative  proportion  of  fiber  increases  and  the  tissue 
becomes  harder  and  more  resisting.  Numerous  Ameri- 
can and  European  digestion  trials  unite  in  testifying 
almost  unanimously  to  a  gradually  diminished  digesti- 
bility as  the  meadow  grasses  increase  in  age.  The  matur- 
ing of  maize  seems  to  produce  quite  the  contrary  effect. 
The  testimony  of  experiments  conducted  at  the  Connec- 
ticut, Maine,  and  Pennsylvania  experiment  stations 
justifies  the  statement  that  the  corn  plant,  cut  when  the 
ears  are  full-grown,  furnishes  not  only  a  larger  amount 
of  digestible  material,  but  a  larger  relative  proportion 
tha,n  when  cut  before  the  ears  have  formed;  and  this  is 
strictly  in  harmony  with  our  general  principle,  for  the 
mature  plant,  on  account  of  the  storage  of  starch  in  the 
kernels,  has  by  far  a  larger  proportion  of  the  more  digesti- 
ble carbohydrates.  (See  Par.  102.) 

186.  Influence  of  methods  of  preparation  of  food. — 
Much  labor  and  expense  have  been  expended  by  farmers 
in  giving  to  feeding-stuffs  special  treatment,  such  as  wet- 
ting,  steaming,    cooking   and   fermenting,   in   order   to 
secure  a  supposed  increase  in  nutritive  value,  an  increase 
which  must  come  chiefly,  if  at  all,  from  a  more  com- 
plete digestion.  It  is  plainly  noticeable  that  these  methods 
of  feeding  have  lost  in  prevalence  rather  than  gained. 


128  THE  FEEDING  OF  ANIMALS 

Practice  does  not  seem  to  have  permanently  ratified 
them,  and,  so  far  as  digestibility  is  concerned,  this  out- 
come is  in  accordance  with  the  results  of  scientific  demon- 
stration. The  conclusions  of  German  experimenters  have 
been  that  these  special  treatments  have  no  favorable 
influence,  their  effect  being  either  imperceptible  or 
unfavorable. 

187.  Wetting  food. — It  should  occasion  no  surprise 
that  the  mere  wetting  of  a  food  is  without  influence  upon 
its  solubility  in  the  digestive  juices,  because  it  becomes 
thoroughly  moistened  during  the  mastication  and  in  the 
stomach.     It  is  not  rational   to   expect   that  previous 
wetting  would  have  the  slightest  effect  unless  it  induced 
more  complete  mastication,  which  certainly  would  not 
be  the  case  with  ground  grains.    The  extensive  trials  by 
Kuhn  and  others  with  a  hay  and  bran  ration,  the  bran 
being  fed  in  several  conditions,  such  as  dry,  wet,  moist- 
ened some  hours  before  feeding,  treated  with  boiling  water, 
and  fermented,  gave  results  adverse  to  all  of  the  special 
methods  of  preparation  as  either  useless  or  harmful,  and 
no  testimony  so  thorough  and  convincing  has  been  fur- 
nished on  the  other  side. 

188.  Cooking  foods. — German  and  American  experi- 
ments unite  in  condemning  the  cooking  of  foods  already 
palatable,  because  this  causes  a  marked  depression  of 
the  digestibility  of  the  protein,  with  no  compensating 
advantages.     Digestion  trials  with  cooked  or  steamed 
hays,  silage,  lupine  seed,  corn  meal  and  wheat  bran,  and 
roasted  cotton  seed,  uniformly  show  their  protein  to  be 
notably  less  digestible  than  that  in  the  original  materials, 
a  fact  which  may  explain  the  lessened  productive  value 
of   cooked  grains  which  has  been  observed  in  certain 
experiments.    It  must  be  conceded,  of  course,  that  when 


CONDITIONS  INFLUENCING  DIGESTION  129 

cooking  feeding-stuffs  by  steaming  or  otherwise  renders 
them  more  palatable,  and  thereby  makes  possible  the 
consumption  of  material  otherwise  wasted,  the  influence 
upon  digestibility  is  a  minor  consideration. 

189.  Influence   of   grinding   foods. — Few   points   are 
more  frequently  questioned  than  the  profitableness  of 
grinding  grain.  There  seem  to  be  only  two  ways  in  which 
such  preparation  can  enhance  the  nutritive  value  of  a 
feeding-stuff,  viz.,  by  diminishing  the  energy  needed  for 
the  digestive  processes  and  by  increasing  the  digesti- 
bility.   While  not  many  experiments  bearing  upon  the 
digestion  side  of  this  question  are  on  record,  their  evi- 
dence is  quite  emphatic.   In  three  trials  with  horses,  with 
corn  and  oats,  grinding  caused  an  increase  of  digesti- 
bility varying  from  3.3  to  14  per  cent.    A  single  experi- 
ment with  maize  kernels  gave  a  greater  digestibility  of 
about  7  per  cent  from  grinding,  and  with  wheat,  in  one 
trial,  the  increase  was  10  per  cent.    In  one  test  with 
sheep,  the  unground  kernels  were  as  completely  utilized 
as  the  ground.     It  is  reasonable  to  expect  that  with 
ruminants  the  danger  of  imperfect  mastication  is  less 
than  with  horses  and  swine,  although  whole  kernels  of 
grain  are  often  seen  in  the  feces  of  bovines.   The  profita- 
bleness of  grinding  grain  turns,  in  part  at  least,  upon  the 
relation  of  the  cost  of  grinding  to  the  loss  of  nutritive 
material  from  not  grinding.    If  the  miller's  toll  amounts 
to  one-tenth  the  value  of  the  grain  the  economy  of  grind- 
ing it  may  be  doubtful,  especially  with  ruminants.    The 
utilization  of  the  undigested  kernels  of  grain  by  pigs  is  a 
business  point  to  be  considered. 

190.  Effect  of  common  salt. — It  is  the  custom   of 
many  feeders  to  allow  their  animals  an  unlimited  supply 
of  salt,  and  others  furnish  it  in  definite  and  regular  quan- 


130  THE  FEEDING  OF  ANIMALS 

titles.  The  belief  prevails  more  or  less  widely  that  an 
abundant  consumption  of  salt  is  beneficial.  If  this  is 
true,  the  advantage  arises  for  other  reasons  than  an 
increased  digestibility.  The  verdict  from  earlier  experi- 
ments by  Grouven,  Hofmeister,  and  Weiske  that  the 
addition  of  salt  to  the  ration  does  not  increase  the  digesti- 
bility was  confirmed  through  later  tests  by  Wolff.  In- 
deed, if  we  give  to  the  data  collected  a  literal  and  per- 
fectly justifiable  interpretation,  salt  diminished  rather 
than  raised  the  proportion  of  digestible  nutrients. 

191.  Influence  of  frequency  of  feeding  and  watering 
animals. — Experiments  relative  to  this  point  are  not 
numerous.'  One  by  Weiske  and  others,  relative  to  fre- 
quency of  feeding,  and  another  by  Gabriel  and  Weiske, 
in  which  the  effects  of  the  tune  of  watering  and  of  the 
amount  of  water  were  tested,  gave  no  indication  that  the 
completeness  of  digestion  is  materially  affected  by  varia- 
tions in  these  details  of  practice.  According  to  Smith, 
horses  should  be  watered  before  being  fed.  He  argues 
that  water  does  not  stop  in  the  stomach  but  passes 
directly  through  it  and  freshly  ingested  food  would  be 
washed  into  the  intestine  before  any  stomach  digestion 
occurs,  an  opinion  which  tallies  with  the  popular  view. 
On  the  other  hand,  Tangl  asserts,  on  the  basis  of  extended 
investigations,  that  horses  may  be  watered  either  before 
or  after  eating  without  depressing  digestion,  except  that 
a  horse  long  deprived  of  water  should  be  watered  before 
eating.  The  thing  chiefly  important  is  that  the  plan  of 
feeding  and  watering  should  not  be  varied.  It  seems 
probable  that  the  nutritive  importance  of  these  minor 
points  in  managing  animals  has  been  much  overesti- 
mated by  some,  especially  as  affecting  the  utilization  of 
the  food. 


CONDITIONS  INFLUENCING  DIGESTION  131 

192.  Influence   of   season   and   storage. — It   is   well 
known  that  the  composition  of  fodder  crops  grown  on  the 
same  soil  may  vary  somewhat  from  year  to  year  accord- 
ing as  the  season  is  wet  or  dry,  cold  or  warm.  Such  varia- 
tions   may    influence    digestibility,   though    no     actual 
demonstration  of  this  fact  appears  to  be  on  record.   The 
question  is  often  asked  whether  the  storage  of  hay  for 
a  long  period  affects  its  nutritive  value.   The  data  from 
four  series  of  experiments  touching  on  this  point  indicate 
that  there  is  a  perceptible,  though  not  marked,  decrease 
in  digestibility  of  hay  during  long-continued  storage. 

193.  Influence  of  the  combination  of  food  nutrients. — 
Among  the  apparently  important  and  freely  exploited 
conclusions  drawn  from  investigations  in  animal  nutri- 
tion is  the  statement  that  the  digestibility  of  food  is 
influenced  to  a  marked  degree  by  the  relative  propor- 
tions of  the  several  classes  of  nutrients.   It  is  taught  that 
if  more  than  a  certain  percentage  of  starch  and  sugar,  or 
of   feeding-stuffs   rich   in   carbohydrates,   like   potatoes 
or  roots,  is  added  to  a  basal  ration,  the  digestibility  of 
the  latter  is  decreased,  the  protein  and  fiber  being  especi- 
ally affected.   The  conclusions,  as  stated  by  Dietrich  and 
Konig,  on  the  basis  of  a  critical  study  of  the  data  involved 
are  that  if  pure  carbohydrates  are  used  to  the  extent  of 
more  than  10  per  cent  of  the  dry  substance  of  a  basal 
ration,  or  if  potatoes  and  roots  are  fed  equivalent  in  dry 
matter  to  more  than  15  per  cent,  a  depression  of  digesti- 
bility occurs,  which  increases  with  the  amount  of  carbo- 
hydrate material  added.   Kellner  taught  that  if  the  crude 
protein  in  a  ration  falls  below  one  part  to  eight  of  digesti- 
ble non-nitrogenous  nutrients  (carbohydrates  +  fat  X  2.25) 
a  depression  digestibility  occurs.     It  is  suggested  that 
when   much    easily   digested    carbohydrate   material    is 


132  THE  FEEDING  OF  ANIMALS 

fed  the  activity  of  the  cellulose  digesting  bacteria  is 
diverted  from  the  crude  fiber  to  the  more  readily  avail- 
able starches  or  sugars.  A  modifying  conclusion  is,  that 
if  the  addition  of  the  carbohydrate  material  is  accom- 
panied by  correspondingly  more  protein,  the  depression 
of  the  digestion  coefficients  is  much  lessened  or  does  not 
occur.  Many  data  are  cited  in  support  of  these  generali- 
zations which  are  worthy  of  careful  consideration. 

It  is  not  unreasonable  to  suppose  that  the  relative 
quantity  in  a  ration  of  the  several  classes  of  nutrients 
may  have  an  influence  upon  the  digestive  processes,  and 
we  should  accept  the  verdict  of  previous  observations  in 
so  far  as  they  will  bear  critical  discussion  and  further 
investigation.  But  it  should  be  said,  by  way  of  comment, 
that  the  carbohydrate  material  in  the  experiments  cited 
has  usually  been  fed  in  addition  to  a  basal  ration,  thus 
increasing  the  amount  of  food  consumed,  and,  as  we  have 
seen,  this  may  have  an  influence  upon  the  proportion  of 
total  dry  matter  digested.  In  this  particular,  the  experi- 
ments have  not  been  logical.  Again,  in  these  experi- 
ments, no  allowance  has  been  made  for  the  metabolic 
wastes  in  the  feces,  i.  e.,  that  material  not  belonging  to 
the  true  undigested  residue.  As  this  appears  to  be  inde- 
pendent of  the  amount  of  protein  fed  and  stands  more 
nearly  in  relation  to  the  total  digested  nutrients,  it  fol- 
lows that  the  smaller  the  proportion  of  protein  in  the 
digested  food,  the  larger  the  error  caused  in  the  coeffi- 
cient for  protein  by  the  waste  nitrogen  products.  A  careful 
study  of  this  point  in  the  light  of  more  recent  knowl- 
edge might  modify  the  conclusion  reached  as  to  the 
depression  of  protein  digestion  through  feeding  starch 
or  -starchy  foods.  In  all  or  nearly  all  the  experiments 
where  this  effect  is  apparently  shown,  the  digestible  dry 


CONDITIONS  INFLUENCING  DIGESTION  133 

matter  of  the  ration  was  largely  increased  and  the  pro- 
tein remained  constant  or  was  diminished.  However, 
the  depression  of  the  digestibility  of  the  crude  fiber  is 
not  easily  explained  on  any  other  ground  than  that  of 
the  influence  of  the  greater  proportion  of  starch. 

What  is  claimed  as  the  effect  of  a  disproportionate 
addition  to  the  supply  of  carbohydrates  does  not  appear 
to  be  true  of  a  similar  increase  in  the  ration  of  fat  and 
easily  digested  protein.  Several  experiments  in  which 
oils  and  albuminoids  have  been  added  freely  to  a  basal 
ration  did  not  indicate  that  such  addition  had  any  mate- 
rial effect  upon  digestibility. 

194.  Influence  of  work. — Such  evidence  as  has  been 
secured  with  both  man  and  farm  animal  indicates  that 
even  severe  labor  has  no  material  influence  upon  diges- 
tion one  way  or  the  other.    Scheunert's  work  with  horses 
leads  him  to  conclude,  however,  that  exercise  improves 
digestion. 

195.  Influence  of  species,  breed,  age,  and  individual- 
ity.— The  conclusion  reached  by  the  early  experimenters 
in  the  field  of  animal  nutrition  that  the  digestive  efficiency 
of  the  several  species  of  ruminants  was  practically  uni- 
form has  not  been  set  aside  by  more  recent  observations. 
The  number  of  experiments  upon  which  this  conclusion 
was  based  was  large,  and  their  verdict  is  not  likely  to  be 
reversed  by  observations  less  extensive  or  less  complete. 

The  following  coefficients  were  obtained  from  German 
trials  with  meadow  hay : 

DRY  SUBSTANCE  DIGESTED  FROM  MEADOW  HAT  (PER  CENT) 

Samples        Best          Medium       Poor 

Sheep   . 42     67     61     55 

Oxen 10     67     64     56 

Horse  18     58     50     46 


134  THE  FEEDING  OF  ANIMALS 

In  nine  American  experiments  the  digestive  efficiency 
of  large  and  small  ruminants  has  been  studied,  steers 
being  compared  with  sheep  and  cows  with  goats.  In 
five  cases,  the  large  animal  digested  from  5  to  14  per  cent 
the  more,  in  three  cases  the  excess  for  the  small  animal 
varied  between  7  and  17  per  cent,  and  in  one  case  there 
was  little  difference.  The  general  effect  of  such  conflict- 
ing results  is  to  confirm  the  older  and  more  numerous 
observations. 

196.  Lower  digestibility  with  horses  for  coarse 
foods. — The  horse  and  ruminants  differ  in  digestive 
capacity  to  a  marked  extent.  The  comparisons  which 
have  been  made  show  a  uniformly  lower  digestive  effi- 
ciency for  coarse  fodders  on  the  part  of  the  former.  It 
appears  that  because  of  less  perfect  mastication,  or  for 
some  other  reason,  the  horse  dissolves  much  less  of  the 
crude  fiber  than  the  steer  or  sheep,  and  the  effect  of  this 
is  prominent  with  hays  and  other  fibrous  materials. 
With  the  grains,  ruminant  and  equine  digestion  is  not 
greatly  unlike,  eight  samples  of  oats  with  sheep  and 
twenty-four  with  the  horse  showing  almost  identical 
digestion  of  the  dry  matter.  With  maize  the  case  is  the 
same.  In  experiments  with  beans,  the  advantage  was 
slightly  with  the  ruminant.  The  difference  between 
bovine  and  equine  digestion  is  certainly  least  with  highly 
digestible  rations  containing  a  minimum  of  fiber.  So 
far  as  we  are  able  to  judge,  swine  digest  concentrated 
food  about  as  do  ruminants.  How  this  is  in  the  case  of 
fodders  we  do  not  know  fully,  but  it  is  shown  that  the 
swine  digest  crude  fiber  quite  freely. 

Past  experiments  have  not  revealed  any  influence  of 
breed  upon  digestive  capacity.  There  is  no  reason  for 
supposing  that  Shorthorn  cattle,  Southdown  sheep,  and 


CONDITIONS  INFLUENCING  DIGESTION  135 

Chester  White  pigs  would  digest  rations  differently  from 
Jerseys,  Merinoes,  and  Yorkshires. 

Young  animals  seem  to  digest  high-quality  coarse 
foods  and  grains  as  efficiently  as  older  ones  of  the  same 
species,  which  is  probably  contrary  to  the  popular  belief. 
There  is  doubtless  a  variation  in  the  digestive  power  of 
individual  animals,  but  the  data  so  far  collected  do  not 
show  this  with  any  degree  of  definiteness.  In  those  in- 
stances where  the  same  four  or  more  steers  or  sheep  have 
been  used  in  determining  the  digestibility  of  several 
feeding-stuffs,  the  highest  coefficients  were  obtained 
sometimes  with  one  animal  and  sometimes  with  another. 

197.  Determination  of  digestibility. — If  we  accept 
as  the  undigested  food  the  dry  matter  of  the  solid  excre- 
ment, which  is  practically  in  accordance  with  the  fact,  we 
have  only  to  subtract  the  dry  fecal  residue  from  the  dry 
matter  of  the  ingested  food  in  order  to  ascertain  the 
amount  and  proportion  digested.  All  digestion  experi- 
ments have  proceeded  on  this  basis.  Animals  have  been 
fed  at  regular  intervals  a  uniform  quantity  of  carefully 
analyzed  food  and  the  feces  have  been  collected,  weighed, 
and  analyzed.  From  the  data  thus  obtained,  the  digestion 
coefficients  have  been  calculated.  The  method  and  the 
mathematics  of  such  experiments  are  so  simple  that  cor- 
rect results  seem  very  easy  to  obtain  and  they  do  possess 
an  accuracy  sufficiently  approximate  to  truth  to  render 
them  useful  in  practice.  As  digestion  trials  are  usually 
conducted,  the  coefficients  of  digestibility  obtained  for 
the  dry  matter  and  total  organic  matter  represent,  we 
have  reason  to  believe,  very  nearly  the  actual  digestible 
matter  in  the  particular  material  studied.  The  propor- 
tions secured  for  particular  classes  of  nutrients  may  be 
less  accurate,  for  reasons  that  will  appear.  We  cannot 


136  THE  FEEDING  OF  ANIMALS 

be  sure,  either,  that  the  digestibility  of  one  hay  applies 
to  another  produced  and  cured  under  totally  differ- 
ent conditions.  The  truth  of  this  latter  -statement  is 
clearly  seen  in  the  effect  of  the  various  factors  upon 
digestibility. 

198.  The  inaccuracies  of  digestion  coefficients. — The 
inaccuracies  of  digestion  coefficients  are  in  part  those 
for  protein  and  fats.  The  errors  in  the  figures  for  protein 
are  caused  by  the  presence  in  the  feces  of  nitrogen  com- 
pounds which  are  not  a  part  of  the  undigested  food  pro- 
tein. (See  Pars.  173,  174.)  These  are  waste  compounds 
which  are  residues  from  the  bile  and  other  digestive  juices, 
epithelial  cells  and  mucus  which  are  carried  along  from 
the  walls  of  the  intestines  during  the  passage  of  the  food. 
Their  quantity  seems  not  to  be  proportional  to  the  pro- 
tein fed,  but  appears  to  be  influenced  more  or  less  by  the 
amount  of  food  digested.  Their  source  is  in  part  the 
"wear  and  tear"  of  the  digestive  apparatus.  It  follows  then 
that  the  less  protein  there  is  in  a  ration,  the  larger  the 
percentage  error  caused  by  these  metabolic  products. 
In  certain  experiments  with  oat  straw,  the  fecal  nitrogen 
has  been  more  than  that  of  the  food,  although  without 
question  much  of  the  straw  protein  was  digested.  It  has 
been  found,  using  the  best  methods  known  for  extracting 
these  waste  products,  that  they  cause  a  much  larger 
error  for  the  protein  of  the  straws  than  for  that  of  the 
legume  hays.  Under  some  conditions,  at  least,  ten  should 
be  added  to  the  coefficients  of  digestibility  of  the  protein 
of  coarse  fodders  as  usually  given  in  the  tables  that  have 
been  compiled. 

Errors  are  caused  in  determination  of  the  digestibility 
of  fat  in  much  the  same  way.  Certain  of  the  bile  residues 
in  the  solid  excrement  are  soluble  in  the  ether  which  is 


CONDITIONS   INFLUENCING  DIGESTION  137 

used  to  extract  the  fats  and  consequently  the  undigested 
fat  appears  to  be  much  larger  than  it  really  is. 

Reference  has  been  made  to  the  return  to  the  intes- 
tinal tract  of  material  that  was  absorbed  into  the  circula- 
tion and  is  in  part  returned  to  the  intestines  for  excre- 
tion, as,  for  instance,  the  phosphorus  of  phytin  and  other 
compounds.  Such  material  is  not  a  part  of  the  undigested 
food  residue. 


CHAPTER  IX 

THE  DISTRIBUTION  AND  USE  OF  THE 
DIGESTED  FOOD 

THE  digested  food,  after  absorption,  all  passes  into 
the  blood,  either  directly  or  indirectly,  and  mixes  with 
it.  The  materials  which  are  to  serve  the  purposes  of 
nutrition  are  now  taken  up  by  a  stream  of  liquid  that  is 
in  constant  motion  through  the  minutest  divisions  of 
every  part  of  the  animal.  Flowing  in  regular  channels 
the  blood  reaches  not  only  the  bones  and  muscular  tis- 
sues, but  it  passes  through  several  special  organs  and 
glands  where  the  nutrients  it  is  carrying  and  certain  of 
its  own  constituents  meet  with  profound  changes.  It  is 
here  that  we  discover  the  manner  in  which  food  is  applied 
to  use  and  what  are  some  of  the  transformations  which 
the  proteins,  carbohydrates,  and  fats  undergo  in  perform- 
ing their  functions. 

In  order  to  follow  intelligently  this  most  interesting 
phase  of  nutrition,  we  must  know  something  of  the  blood 
and  of  the  organs — the  lungs,  liver,  and  kidneys — through 
which  it  passes. 

199.  The  blood. — The  blood,  which  makes  up  from 
3  to  4  per  cent  of  the  total  weight  of  the  live  animal, 
when  in  a  fresh  state,  is  apparently  colored  and  opaque, 
but  if  a  minute  portion  is  examined  with  a  microscope,  it 
is  seen  to  be  a  comparatively  clear  liquid  in  which  float 
numerous  reddish  disk-like  bodies.  These  bodies,  which 
are  known  as  corpuscles,  give  to  the  blood  its  bright  red 

(138) 


USE  OF   THE  DIGESTED   FOOD 


139 


color.    The  liquid  in  which  they  are  suspended  is  called 
the  plasma. 

200.  The  blood  corpuscles  (Fig.  6). — The  corpuscles 
are  not  mere  masses  of  unformed  matter,  but  they  are 
minute  bodies  having  a  definite  form  and  structure.  They 
make  up  from  35  to  40  per  cent  of  the  blood,  and  con- 
tain over  30  per 
cent  of  dry 
matter.  This 
dry  matter  con- 
sists mostly  of 
hemoglobin,  a 

compound    that        ^  Slgg 

is  peculiar  to  the 
blood  and  equips 
it  for  one  of  its 
most  important 
offices.  Hemo- 
globin, when 
broken  up  in  the 
absence  of  oxy- 
gen, is  found  to 
be  made  up  of  a 
protein  (globin- 
histone)  and  a 
coloring  matter 
(hemochromogen)  in  the  latter  of  which  is  combined  a 
definite  proportion  of  iron.  When  broken  up  in  the  pres- 
ence of  oxygen  we  get  globin  and  hematin,  as  hemo- 
chromogen when  oxydized  becomes  hematin.  The  peculiar 
property  of  hemoglobin  which  renders  it  so  useful  a  con- 
stituent of  the  blood  is  its  power  of  taking  up  oxygen 
and  holding  it  in  a  loose  combination  until  it  is  needed 


FIG.  6.  Red  and  white  corpuscles  of  blood 
(magnified).  A,  red  corpuscles;  a,  a,  white  cor- 
puscles; B,  C,  D,  red  corpuscles,  more  highly 
magnified;  F,  G,  white  corpuscles,  more  mag- 
nified. 


140  THE  FEEDING  OF  ANIMALS 

for  use.  When  thus  charged,  it  is  known  as  oxyhemo- 
globin.  Because  of  this  function  of  their  most  prominent 
constituent,  blood  corpuscles  become  the  carriers  of 
oxygen  to  all  parts  of  the  body.  The  blood  corpuscles 
are  also  concerned  in  gathering  up  one  of  the  waste 
products  of  metabolism,  viz.,  carbon  dioxid,  and  convey- 
ing it  to  the  point  where  it  may  be  thrown  off  from  the 
body.  (See  Par.  77.) 

201.  The    blood   plasma. — The    plasma    is   a   liquid 
having  a  very  complex  composition.    It  is  about  nine- 
tenths  water,  so  that  it  easily  holds  in  solution  whatever 
soluble  nutrients  are  discharged  into  it  from  the  alimen- 
tary canal.  Among  its  constituents  are  found  members  of 
all  the  classes  of  compounds  that  are  important  in  this 
connection — ash,  protein,  carbohydrates,  and  fats.    The 
proportion  of  ash  is  about  1  per  cent,  three-fourths  of  it 
being   common   salt,   and   the   remainder   consisting   of 
phosphoric  acid,  lime,  and  other  important  mineral  com- 
pounds.   The  solid  matter  of  the  plasma  is  rich  in  pro- 
teins, including  the  fibrinogen  which  is  the  mother  sub- 
stance  of   fibrin   and   several   albumins   and   globulins. 
These  proteins  make  up  about  80  per  cent  of  the  total 
dry  substance  of  plasma.   Sugar  and  fats  are  also  present, 
their  proportions  undoubtedly  varying  somewhat  with 
the  extent  to  which  they  are  being  absorbed  from  the 
digestion  of  food.    It  is  evident  that  the  blood  is  charged 
with  those  materials  which  we  recognize  as  necessary  to 
the  construction  and  maintenance  of  the  animal  body. 

202.  The  heart.— The  blood  is  contained  in  the  heart 
and  in  two  sets  of  vessels,  one  set  called  the  arteries  lead- 
ing from  the  heart  by  various  ramifications  to  all  parts 
of  the  body,  and  the  other  set  called  the  veins,  leading 
from  all  parts  of  the  body  back  to  the  heart.    Through 


USE   OF   THE   DIGESTED   FOOD 


141 


142 


THE  FEEDING  OF  ANIMALS 


these  vessels  the  blood  is  mov- 
ing in  a  constant  stream,  which 
we  call  the  circulation.  It  does 
not  move  of  itself,  but  is  forced 
along  by  a  very  powerful  pump, 
the  heart.  This  is  a  highly 
muscular  organ  divided  into 
four  chambers,  which  are  sepa- 
rated by  valves  and  partitions, 
the  two  upper  chambers  being 
called  the  right  and  left  auri- 
cles, and  the  two  lower  the  right 
and  left  ventricles.  The  right 
auricle  is  above  the  right  ventri- 
cle and  is  separated  from  it  by 
a  valve,  and  the  same  is  true 
of  the  left  auricle  and  ventricle. 
(Fig.  7.) 

203.  Circulation  of  blood.— 
Out  of  the  left  ventricle  the 
blood  is  pumped  into  the  arteries 
and,  after  reaching  the  arterial 
capillaries  throughout  the  entire 
body,  it  passes  from  these  into 
the  smallest  divisions  of  the 
veins  and  comes  back  to  the 
heart  along  the  venous  system, 
entering  the  right  auricle.  It 
is  then  carried  to  the  lungs  by 


FIG.  8.  Diagram  of  circulation.  1, 
heart;  2,  lungs;  3,  head  and  upper 
extremities;  4>  spleen;  5,  intestine;  6, 
kidney;  7,  lower  extremities;  8,  liver. 
(Collins.) 


USE  OF   THE  DIGESTED  FOOD  143 

way  of  the  right  ventricle  and  is  returned  from  the 
lungs  to  the  left  auricle  to  be  sent  to  the  left  ventricle, 
and  from  there  to  again  start  on  its  journey  through 
the  body.  (Fig.  8.) 

The  nutrients,  as  prepared  for  use  by  digestion,  enter 
the  blood  on  its  return  flow  to  the  heart,  coming  into 
the  venous  cavity  by  way  of  the  hepatic  (liver)  vein  and 
the  thoracic  duct  as  previously  described.  When,  there- 
fore, the  right  side  of  the  heart  is  reached,  a  new  acces- 
sion of  food  material  is  on  its  way  to  sustain  the  various 
functions  of  nutrition. 

We  are  more  interested  in  the  object  of  blood  circu- 
lation than  we  are  in  its  mechanism.  Somehow  the 
digested  food  disappears  into  these  constantly  moving 
blood  currents,  and  the  only  evidence  of  its  effect  which 
comes  to  us  from  ordinary  observation  is  the  warmth, 
motion,  and  perhaps  growth  of  the  animal  that  is 
nourished. 

204.  The  lungs. — The  first  point  where  important 
changes  occur  is  the  lungs.  Here  the  blood  loses  the  pur- 
plish hue  which  it  always  has  after  being  used  in  the  body 
tissues  and  takes  on  a  bright  scarlet,  a  phenomenon  that 
is  more  easily  explained  when  we  understand  the  lung 
structure.  (Fig.  9.) 

Breathing  is  a  matter  of  common  experience.  We  all 
know  how  air  is  drawn  into  the  lungs  at  regular  intervals, 
an  equivalent  quantity  being  as  regularly  forced  out. 
The  mechanism  of  respiration  (breathing)  we  will  not  dis- 
cuss at  length.  It  will  aid  us,  however,  if  we  know  that 
the  passage  which  the  air  follows  to  and  from  the  lungs, 
the  trachea  (windpipe),  divides  into  two  branches,  one  to 
each  lung,  and  these  divide  and  sub-divide  until  they 
branch  into  numerous  fine  tubes.  Each  of  these  tubes 


144 


THE  FEEDING  OF  ANIMALS 


ends  in  an  elongated  dilation  which  is  made  up  of  air 
cells  opening  into  a  common  cavity.  These  cells  are  so 
numerous  in  the  lung  tissues  that  only  a  very  thin  wall 
separates  adjoining  ones,  and  in  this  wall  are  carried  the 


OPPER  LOBB 


RJGJHT  LUNQ 
FIG.  9.    Air-tubes  of  the  human  lung.    (Gerrish.) 

capillaries  or  fine  divisions  of  the  blood  vessels  leading 
from  the  heart. 

205.  Object  of  respiration. — The  lung  structure  per- 
mits the  blood  to  take  up  oxygen  as  it  flows  along  and 
transfer  certain  wastes  into  the  lung  cavities,  and  thus  be 
made  ready  to  go  back  to  the  body  carrying  a  joint  load 
of  digested  food  and  oxygen.  The  air  that  passes  out  of 


USE  OF   THE  DIGESTED   FOOD  145 

the  lungs  is  less  rich  in  oxygen  than  when  it  was  taken  in, 
and  there  have  been  added  to  it  certain  materials  which 
are  noticed  later. 

206.  The    use  of  food. — The  revivified    blood  now 
passes  to  all  parts  of  the  body  and  is  brought  into  the 
most  intimate  relation  with  the  minutest  portion  of  every 
tissue.  Several  things  happen  in  the  course  of  time. 

In  the  first  place,  the  new  supply  of  nutritive  sub- 
stances is  used  by  the  living  cells  in  a  way  we  do  not 
wholly  understand  to  rebuild  worn-out  tissue  and  to 
form  new  growth.  With  the  young  animal,  much  material 
is  appropriated  in  the  latter  way.  In  the  case  of  the  milch 
cow,  there  is  furnished  to  the  udder  the  nutrients  out  of 
which  certain  constituents  of  milk  are  formed  through  the 
special  activities  of  that  gland. 

207.  Nutrients  are  oxidized. — Moreover,  it  is  in  the 
tissues  that  the  oxygen  which  was  taken  up  in  the  lungs 
is  used  to  burn  slowly  a  portion  of  the  food.   This  com- 
bustion does  not  take  place  by  the  mere  contact  of  the 
oxygen  and  food  in  the  large  blood  vessels,  but  it  occurs 
by  progressive  steps  throughout  the  minute  divisions  of 
the  muscles  and  other  parts  of  the  whole  body^   Not- 
withstanding this  oxidation  may  be  very  gradual  and 
occupy  much  time,  its  ultimate  products  are,  for  the  most 
part,  similar  to  those  which  result  from  the  rapid  com- 
bustion of  fuel.    In  the  fireplace,  starch,  sugar,  cellulose, 
fats,  and  similar  bodies  would  be  burned  to  carbonic  acid 
and  water,  and  this  is  what  takes  place  in  the  animal  to 
the  extent  that  these  nutrients  are  not  used  for  the  forma- 
tion of  body  substance.    When  the  protein  is  not  stored 
as  such  but  is  broken  up,  the  result  differs  somewhat  in 
the  furnace  and  in  the  animal  because  in  the  latter  the 
oxidation  is  not  complete. 

j 


146  THE  FEEDING  OF  ANIMALS 

208.  Oxidases. — The  manner  of  this  oxidation  is  one 
of  the  difficult  physiological  problems.  The  present  view, 
and  one  based  on  very  significant  data,  is  that  these 
oxidations  of  the  nutrients  is  the  result  of  enzym  action 
and  the  oxidizing  ferments  are  designated  as  oxidases. 
The  proteins,  carbohydrates,  and  fats  are  first  acted  on 
during   digestion   by   the  hydrolizing   enzyms,  and   the 
cleavage   products   are   then   further   broken   down,   or 
oxidized,  by  the  oxidases. 

209.  Proteins  not  wholly  oxided. — The  proteins  may 
be  partially  burned  to  carbonic  acid  and  water,  but  unless 
used  for  tissue  formation  a  portion  of  their  substance 
passes  from  the  body  principally  in  the  form  of  urea  and 
uric  acid,  which  are  the  prominent  constituents  of  urine. 
These  compounds  carry  with  them  a  certain  proportion 
of  carbon  and  hydrogen  which  in  ordinary  fuel  com- 
bustion would  more  fully  unite  with  oxygen.    The  heat 
production  from  protein  is  therefore  less  in  the  animal 
than  in  the  furnace. 

210.  Rate  of  oxidation  of  nutrients. — This  oxidation 
in  the  animal  is  constant  but  not  uniform.   It  varies  with 
the  exercise  the  animal  is  taking  and  with  the  amount  of 
food  that  must  be  disposed  of.    The  quantity  of  oxygen 
needed  is  therefore  variable,  and  when  the  demand  for  it 
is  largely  increased  the  heart  pumps  faster,  more  blood 
passes  through  the  lungs,  the  breathing  is  more  rapid  and 
the  supply  of  oxygen  is  in  this  way  augmented. 

ELIMINATION   OF  WASTES 

The  various  waste  products  from  this  combustion  and 
from  the  breaking  up  of  the  proteins  within  the  animal 
evidently  must  be  disposed  of  in  some  manner.  When 


USE  OF   THE  DIGESTED   FOOD  147 

not  eliminated  from  the  body,  they  cause  results  of  a 
most  serious  character,  as,  for  instance,  when  an  accumu- 
lation of  urea  in  the  body  produces  ursemic  poisoning. 
The  blood  therefore  not  only  carries  to  the  tissues  the 
necessary  nutrients  and  oxygen,  but  it  has  laid  upon  it 
the  burden  of  taking  into  its  currents  the  waste  products 
of  combustion  and  growth  and  carrying  them  to  the 
points  where  they  are  thrown  off.  (See  Par.  77.) 

211.  Elimination  of  urea. — One  of  the  branches  of  the 
arterial  system  of  blood  vessels  runs  to  the  kidneys,  and, 
by  repeatedly  rebranching,  traverses  all  their  substance. 
The  main  function  of  the  kidneys  is  to  eliminate  certain 
products  through  the  urine.   It  is  in  this  way  that  all  the 
waste  nitrogen  from  the  digested  protein  finds  its  way  out 
of  the  body  in  the  form  of  urea  and  similar  bodies.   The 
blood  that  enters  them  carries  with  it  the  urea  and  uric 
acid  which  have  resulted  from  a  breaking  down  of  pro- 
tein, and  in  a  most  wonderful  manner  these  compounds 
are  filtered  out  so  that  they  are  not  present  in  the  out- 
going blood.  An  excess  of  soluble  mineral  matters,  espec- 
ially the  alkaline  salts  is  also  removed  by  the  kidneys,  as 
well  as  the  bile  compounds  which  are  absorbed  from  the 
alimentary  canal. 

212.  Elimination     of    carbon     dioxid. — The    carbon 
dioxid  must  in  some  way  also  be  eliminated  from  the 
body.    This  is  not  accomplished  to  any  extent  until  the 
blood  containing  it  reaches  the  lungs,  where  it  is  ex- 
changed for  a  new  supply  of  oxygen  and  passes  off  in  the 
expired  air.    In  the  case  of  man,  the  air  "breathed  out" 
is  nearly  a  hundred  times  richer  in  carbonic  acid  than  the 
air  "breathed  in." 

213.  Elimination  of  water. — Water  may  be  regarded 
from  one  point  of  view  as  a  waste,  for  it  is  produced  in 


Fio.  10.  Portal  system  of  veins  in  the  human  subject,  showing  how 
absorbed  nutrients  are  collected  from  intestinal  tract  and  carried  to 
liver  by  portal  vein. 

(148) 


USE  OF   THE  DIGESTED   FOOD  149 

the  oxidation  of  the  food,  and  this  passes  off  from  the 
lungs  as  vapor,  through  the  skin  as  sensible  or  insensible 
perspiration,  and  in  considerable  quantities  through  the 
kidneys. 

To  summarize,  it  may  be  said  that  the  blood  is  con- 
stantly undergoing  gain  and  loss.  The  gain  comes  from 
the  food  (including  water  and  oxygen),  and  the  loss  con- 
sists of  the  compounds  in. the  urine,  carbonic  acid,  and 
water  given  off  through  various  channels. 

THE   LIVER 

214.  Regulation  of  carbohydrate  use. — One  part  of 
the  arterial  system  of  blood  vessels  runs  to  the  stomach 
and  intestines  and  is  distributed  over  their  walls  in  fine 
divisions.  These  connect  with  the  capillaries  of  the  portal 
vein  which  leads  to  the  liver  (Fig.  10).  During  this  passage 
of  the  blood  from  one  system  to  the  other,  part  of  the 
digested  food  is  taken  up.  The  quantity  of  material  thus 
absorbed  must  vary  greatly  at  different  times  according  to 
the  nature  and  amount  of  food  supply  and  the  activity  of 
the  digestive  processes.  If,  therefore,  the  blood  from  the 
alimentary  canal  were  allowed  to  pass  directly  into  the 
general  circulation,  the  supply  to  the  tissues  of  the  sugar 
resulting  from  digestion  would  be  very  uneven.  Just  here 
comes  in  a  liver  function.  In  that  organ  there  is  found  a 
starch-like  body  known  as  glycogen,  which  appears  in 
increased  quantity  following  the  abundant  absorption 
of  sugar  from  the  intestines.  It  is  believed,  because  of 
this  and  other  facts,  that  the  liver  acts  as  a  regulator  of 
the  carbohydrate  supply  to  the  general  tissues  of  the 
body,  storing  a  temporary  excess  of  the  sugar  in  the  form 
of  glycogen  and  then  gradually  giving  it  up  to  the  gen- 


150  THE  FEEDING  OF  ANIMALS 

eral  circulation  as  it  is  needed.  Glycogen  is  also  stored  in 
the  muscles  in  an  amount  equal  to  or  greater  than  in 
the  liver.  (See  Par.  103.)  No  better  illustration  can  be 
cited  of  the  nicety  of  adjustment  of  the  animal  organism 
to  the  maintenance  of  its  activities  than  this  regulation 
of  its  fuel  supply  to  the  areas  of  oxidation. 


CHAPTER  X 
THE  FUNCTIONS  OF  THE  NUTRIENTS 

THE  digestion,  absorption,  and  distribution  of  food 
are  not  its  use — they  are  the  preliminaries  necessary  to 
use.  Not  until  the  nutrients  have  been  converted  to 
available  forms  and  have  passed  into  the  blood  do  they 
in  the  slightest  degree  furnish  energy  or  building-material 
to  the  animal  organism.  We  have  followed  to  a  certain 
extent  the  chemical  changes  which  the  digested  food 
suffers,  but  no  detailed  statements  have  been  made  as 
to  the  part  taken  by  each  class  of  nutrients  in  constructing 
the  animal  body  and  in  maintaining  its  complex  activities. 

215.  General  uses  of  food. — Animals  use  food  in  two 
general   ways,    viz.,    for   constructive   purposes,   which 
involve  the  building  or  repair  of  tissue  and  the  forma- 
tion of  milk,  and  as  fuel  for  supplying  different  forms 
of  energy.    The  tissues  which  are  to  be  formed  are  of 
several  kinds,  principally  the  mineral  portion  of  the  bone, 
the  nitrogenous  tissue  of  the  muscles,  tendons,  skin,  hair, 
horn,  and  various  organs  and  membranes,  and  the  deposits 
of  fat  which  are  quite  generally  distributed  throughout 
the  body  substance. 

216.  Uses  of  energy. — Energy  in  the  forms  in  which  it 
is  used  by  the  animal  organism  may  appear  as  muscular 
activity,  both  internal  and  external,  such  as  working, 
walking,  breathing,  the  beating  of  the  heart,  the  move- 
ments of  the  stomach  and  intestines,  as  heat,  and  as 
chemical  energy  necessary  for  carrying  on  digestion  and 

(151) 


152  THE  FEEDING  OF  ANIMALS 

other  metabolic  changes.  The  animal  body  is  certainly 
the  seat  of  greatly  varied  and  complex  constructive  and 
destructive  activities,  which  are  sustained  by  the  matter 
and  potential  energy  of  the  food.  How  this  is  done  we 
do  not  fully  understand,  but  we  know  many  facts  which 
are  of  great  scientific  and  practical  importance  and  which 
the  feeder  must  consciously  or  unconsciously  recognize 
if  he  would  not  come  into  conflict  with  immutable  laws. 
(See  Pars.  236-241.) 

217.  Functions    of    water. — Water    fills    an   impor- 
tant place  in  the  nutrition  of  all  forms  of  life.    In  both 
plants  and  animals  it  acts  as  a  solvent  of  the  building- 
materials  which  it  carries  from  one  part  of  the  organism 
to  another.   It  also  serves  as  a  carrier  of  wastes,  particu- 
larly those  excreted  through  the  kidneys,  and  the  free 
use  of  water  is  recommended   as  promoting  thorough 
cleansing  of  the  tissues.    It  is  proper  to  speak  of  water 
as  building-material  for  the  animal  body,  for  it  is  an 
abundant  constituent  of  animal  tissue  and  takes  part  in 
chemical  changes  such  as  hydrolysis.   It  fills  an  essential 
office  in  regulating  the  heat  processes  of  the  body  through 
varying  rates  of  evaporation  from  the  surface  of  the  body. 

FUNCTIONS   OF  THE   MINERAL   ELEMENTS 

218.  Relation  of  mineral  elements  to  vital  processes. — 
The  life  of  an  animal  is  maintained  through  chemical 
reactions  between  substances  in  solution.  These  reactions 
are  brought  about  by  means  of  electrical  currents,  and 
the  importance  of  the  mineral  salts  in  these  relations  is 
seen  in  the  fact  that  very  dilute  solutions  of  the  mineral 
salts  in  water  increase  greatly  the  electrical  conductivity. 
The  organic  compounds  in  the  body  have  a  low  electrical 


FUNCTIONS   OF   THE  NUTRIENTS 


153 


conductivity  or  are  inert,  and  it  is  the  presence  of  the 
mineral  elements  in  solution  carrying  electrical  charges 
which  makes  possible  the  reactions  involved  in  metabolism. 
Without  the  mineral  elements  protoplasm  would  be  dead. 
219.  Relation  of  mineral  elements  to  animal  struc- 
ture.— The  mineral  elements  are  largely  involved  in  the 
structure  of  the  animal  body.  They  constitute  the  entire 
amount  of  the  ash  in  which  the  elements  calcium  and 
phosphorus  exist  in  the  largest  proportions.  The  follow- 
ing table  illustrates  the  kinds  and  distribution  of  mineral 
elements  in  the  bodies  of  five  species  of  farm  animals. 

TABLE  XXVII 


Ox 

Calf 

Sheep 

Lamb 

Pig 

Half 
fat 

Fat 

Fat 

Thin 

Half 

fat 

Fat 

Very 
fat 

Fat' 

Thin 

Fat 

Fat   
Nitrogenous 
matter      .    .    . 
Minerals       .    .    . 
Water       .... 
Contents  of 
stomach,  etc. 

Per 
cent 

19.1 

16.6 
4.66 
51.5 

8.2 

Per 
cent 

30.1 

14.5 
3.92 
45.5 

6. 

Per 
cent 

14.8 

15.2 
3.8 
63. 

3.2 

Per 

cent 

18.7 

14.8 
3.16 
57.3 

6. 

Per 
cent 

23.5 

14. 
3.17 
50.2 

9.1 

Per 

cent 

35.6 

12.2 

2.81 
43.4 

6. 

Per 

cent 

45.8 

10.9 
2.9 
35.2 

5.2 

Per 

cent 

28.5 

12.3 
2.94 

47.8 

8.5 

Per 
cent 

23.3 

13.7 
2.67 
55.1 

5.2 

Per 
cent 

42.2 

10.9 
1.65 
41.3 

4. 

Total    

100. 

100. 

100. 

100. 

100. 

100. 

100. 

100. 

100. 

100. 

Minerals 

Phosphorus      .    . 
Calcium   .... 
Magnesium      .    . 
Potassium    .    .    . 
Sodium     .... 
Iron  .    .    . 

Per 
cent 

.803 
1.508 
.051 
.17 
.108 
.028 
.015 

Per 
cent 

.677 
1.281 
.037 
.146 
.094 
.017 
.013 

Per 

cent 

.67 
1.177 
.048 
.171 
.109 
.015 
.016 

Per 
cent 

.488 
.944 
.034 
.144 
.09 
.026 
.021 

Per 
cent 

.524 
.965 
.031 
.14 
.077 
.029 
.014 

Per 

cent 
.454 
.846 
.029 
.123 
.072 
.024 
.012 

Per 
cent 
.484 
.886 
.033 
.131 
.096 
.021 
.011 

Per 

cent 
.492 
.915 
.031 
.138 
.076 
.018 
.016 

Per 

cent 
.465 
.771 
.032 
.163 
.082 
.015 
.021 

Per 
cent 
.286 
.455 
.019 
.115 
.054 
.009 
.012 

Sulfur       .... 

Live  weight,  Ibs. 
Age 

1,232 

4yrs. 

1,419 
4yrs. 

258.8 
9.5 
wks. 

97.6 

lyr. 

105.1 

VA 

yrs. 

127.2 
1M 

yrs. 

239.4 

IX 

yrs. 

84.4 

Hyr. 

93.9 

185. 

154  THE  FEEDING  OF  ANIMALS 

220.  Distribution  of  mineral  elements  in  animal  body. 
— The  bones  carry  the  greater  part  of  the  ash  elements. 
Fresh  bones  are  approximately  one-quarter  ash.    The 
muscles  have  between  1  and  2  per  cent  of  ash,  and  the 
blood  from  eight  to  nine  parts  in  a  thousand.   The  dis- 
tribution of  the  mineral  elements  in  the  animal  body  is 
somewhat  as  follows:  phosphorus  and  calcium  predom- 
inate in  the  bones;  sodium  salts  are  found  largely  in  the 
blood,  the  serums,  and  lymph;  potassium  salts  exist  most 
abundantly  in  the  blood,  muscles,  brain,  and  liver.   Iron 
compounds  are  found  most  largely  in  the  blood,  lungs, 
liver,  and  spleen;  and  magnesium  in  the  lungs,  muscles, 
and  nervous  tissue.    Sulfur,  as  has  been  seen,  is  asso- 
ciated with  many  of  the  proteins  and  is  found  in  espec- 
ially large  proportions  in  hair  and  horn. 

221.  Relation  of  mineral  elements  to  elimination  of 
waste  products. — In  this  respect,  iron  exercises  a  particu- 
larly important  function.    As  has  been  seen,  it  is  con- 
tained in  the  hemoglobin  of  the  red  corpuscles.    In  the 
lungs,  oxygen  becomes   lightly  attached   to  this  hemo- 
globin and  is  carried  to  the  various  parts  of  the  body 
where  it  is  used  for  the  oxidation  of  the  organic  com- 
pounds in  the  food.    The  red  corpuscles  seize  upon  the 
carbon  dioxid  which  is  one  of  the  products  of  this  oxida- 
tion and  carry  this  to  the  lungs  where  it  is  eliminated. 
As  these  oxidation  processes  furnish  the  energy  for  sus- 
taining the  activities  of  the  animal  body,  it  appears  that 
iron  is  a  most  important  factor  in  animal  metabolism. 

222.  Relation  of  mineral  elements  to  a  proper  equilib- 
rium between  the  acids  and  bases  of  the  animal  body. — 
The  cleavage  processes  which  take  place  hi  the  use  of 
food  compounds  give  rise  to  sulphuric  and  phosphoric 
acids,  and  these  together  with  certain  organic  acids  must 


FUNCTIONS  OF   THE  NUTRIENTS  155 

be  neutralized  through  the  presence  of  certain  basic  ele- 
ments. Sodium,  potassium,  and  calcium  function  in 
this  relation.  If  this  neutralization  did  not  occur,  the 
animal  would  be  seriously  affected  and  in  time  die.  As  a 
matter  of  fact  acidosis  (acid  condition)  has  not  been 
demonstrated  with  farm  animals.  The  acidity  or  the 
alkalinity  determines  the  function  of  the  action  of  certain 
enzyms  in  the  digestion  of  food,  as,  for  instance,  while  the 
pepsin  of  the  stomach  acts  most  effectively  in  an  acid 
solution,  the  trypsin  and  other  enzyms  of  the  duodenum 
act  only  in  an  alkaline  medium. 

223.  Relation    of    mineral    elements    to   osmosis. — 
The  transference  of  substances  in  solution  from  one  part 
of  the  body  to  another  involves  the  passage  of  solutions 
through  various  membranes  and  tissues,  as,  for  instance, 
from  the  alimentary  canal  into  the  blood  and  from  the 
blood  into  various  tissues  which  are  nourished  through 
such  distribution.   The  penetrability  of  these  membranes 
seems  to  be  dependent  upon  the  presence  of  mineral  salts. 

224.  Relation  of  mineral  elements  to  muscular  con- 
trol.— The  contraction  of  both  the  voluntary  and  invol- 
untary muscles  seems  to  be  dependent  upon  a  certain 
balanced  chemical  environment  involving  salts  of  calcium, 
magnesium,  sodium,  and  potassium. 

225.  Relation  of  mineral  elements  to  tissue  develop- 
ment.— It  has  been  shown  that  the  eggs  of  certain  marine 
fishes  segment  normally  only  in  water  containing  a  mix- 
ture of  certain  salts  of  a  certain  concentration,  these 
being  the  salts  of  the  alkalies  and  alkaline  earths. 

226.  General  considerations. — It  is  easily  seen  that 
the  mineral  salts  sustain  very  complex  relations  to  the 
growth  of  animal  tissue  and  to  the  maintenance  of  animal 
life.   It  is  a  matter  of  common  observation  that  when  an 


156  THE  FEEDING  OF  ANIMALS 

animal  is  given  food  free  from  the  compounds  of  the 
mineral  elements,  the  animal  suffers  physical  deteriora- 
tion and  finally  dies.  In  considering  the  matter  of  a 
sufficient  supply  of  mineral  element,  the  feeder  should 
consult  tables  showing  the  ash  composition  of  the  various 
feeding-stuffs. 

227.  Supply  of  mineral  elements  (see  Pars.  48-54). — 
The  supply  of  the  mineral  elements  in  the  food  of  the 
various  classes  of  animals  has  not  until  a  comparatively 
recent  time  received  extensive  consideration.  It  has  been 
practically  held  that  nature  has  made  a  generous  provision 
for  supplying  the  animal's  needs  for  mineral  substances 
in  our  home-raised  feeding-stuffs  and  that  mixed  rations 
as  usually  fed  contain  in  variety  and  quantity  all  that  is 
needful  of  these  nutrients  for  the  various  kinds  of  pro- 
duction. It  was  clearly  proved  .sometime  since  that  an 
extra  supply  of  mineral  compounds  is  needed  for  laying 
hens,  especially  calcium  compounds  for  the  formation 
of  egg  shell,  and  it  was  also  shown  that  the  proper  devel- 
opment of  the  bony  structure  of  swine  is  not  secured 
through  feeding  cereal  products  alone,  particularly  exclu- 
sive corn-feeding,  but  the  mixed  rations  for  bovine  pro- 
duction have  not  been  questioned  in  this  direction. 

It  has  remained  for  Forbes  in  a  recent  extensive  and 
exceedingly  important  investigation  as  to  the  mineral 
supply  of  liberally  producing  cows  to  show  that  during 
full  milk  production,  even  when  the  animals  were  fed 
on  rations  that  are  regarded  in  practice  as  highly  satis- 
factory, there  were  important  losses  of  calcium,  mag- 
nesium, and  phosphorus  from  the  cow's  skeleton.  It  is 
suggested  that  the  decreasing  milk-supply  during  a 
given  period  of  lactation  and  the  sometimes  observed 
failure  of  a  highly  producing  cow  to  carry  her  high  pro- 


FUNCTIONS  OF   THE  NUTRIENTS  157 

duction  successfully  through  two  periods  of  lactation  are 
due  to  the  removal  from  the  body  of  these  mineral  elements 
not  supplied  in  sufficient  abundance  in  food.  It  would 
seem,  however,  that  ordinarily  there  are  periods  during 
which  a  milch  cow  recovers  her  loss  of  mineral  elements. 

Forbes  calls  attention  to  the  importance  of  iodine  in 
animal  metabolism.  It  has  long  been  known  that  in  the 
cases  of  abnormal  physical  development  accompanied 
by  inferior  intellectual  quality,  such  subjects  being  known 
as  cretins,  the  physical  and  mental  conditions  have  been 
improved  by  an  extract  of  the  thyroid  gland  which  car- 
ries iodine.  An  extensive  investigation  of  many  feeding- 
stuffs  shows  an  absence  of  iodine  in  some  and  only  traces 
or  very  small  percentages  in  others.  It  would  appear, 
however,  that  under  the  ordinary  system  of  feeding  mixed 
rations  the  iodine  supplied  to  our  domestic  animals 
is  sufficient. 

228.  Relative  efficiency  of  different  phosphorus  com- 
pounds.— The  mineral  elements  of  foods  may  be  supplied 
to  the  animal  in  various  forms.  This  is  particularly  true 
of  phosphorus  which  is  used  so  freely  by  growing  animals 
and  milch  cows.  Because  of  the  importance  of  this  ele- 
ment the  problem  of  the  relative  nutritive  efficiency  of 
organic  as  compared  with  inorganic  phosphorus  com- 
pounds has  been  much  studied.  The  organic  forms  found 
in  foods  are  in  part  nucleo-proteins,  phospho-proteins, 
phytin,  and  similar  compounds  found  in  grains,  and 
lecithin  and  glycero-phosphates.  In  an  admirable  re*sume* 
of  the  whole  subject,  Forbes  shows  that  the  data  secured 
on  this  question  give  conflicting  testimony  but  that  the 
majority  of  evidence  seems  to  favor  the  conclusion  that 
the  organic  phosphorus  compounds  are  more  efficient, 
for  some  species  at  least,  than  the  inorganic,  such  as  cal- 


158  THE  FEEDING  OF  ANIMALS 

cium  phosphate.  It  seems  clear,  however,  that  growth 
can  be  secured  where  only  inorganic  phosphorus  is  fed, 
and  in  many  experiments  this  form  has  seemed  as  efficient 
as  the  organic.  The  synthesis  in  the  animal  of  such  com- 
pounds as  the  nucleo-proteins  can  hardly  be  doubted. 
The  fact  of  such  synthesis  does  not  show  that  organic 
phosphorus  compounds  may  not  be  in  general  more 
efficient  than  inorganic.  This  question  has  some  economic 
importance  because  it  is  well  to  know  whether  so  cheap 
a  material  as  phosphatic  rock  may  be  a  useful  source  for 
fortifying  the  phosphorus  supply  of  a  ration. 

FUNCTIONS   OF  PROTEIN 

229.  Proteins  as  tissue-formers. — While  there  are  at 
present  many  unsolved  problems  relative  to  the  nutri- 
tive offices  of  protein,  there  is  no  reasonable  doubt  that 
the  vegetable  proteins  are  the  primary  and  main  source 
of  all  similar  substances  in  the  animal  body.  From  these 
proteins  are  formed  the  muscles,  the  connective  tissues, 
the  skin,  hair,  horn,  and  hoofs,  and  the  major  part  of 
the  tissues  of  the  secretive  and  excretive  organs;  in  short, 
that  they  are  the  source  of  a  large  proportion  of  the 
working  parts  of  the  animal  body.  So  far,  scientific 
research  has  not  succeeded  in  demonstrating  that  a  pro- 
tein is  ever  synthesized  (built  up  from  simple  compounds) 
outside  of  the  plant.  It  appears  that  bodies  of  this  class 
must  in  the  main  come  to  animal  life  fully  elaborated. 
This  is  a  truth  of  great  significance  even  in  its  relation 
to  the  nutrition  of  farm  animals.  The  nitrogenous  tissues 
are  those  that  largely  determine  the  vigor  and  quality 
of  any  animal,  and  as  these  are  formed  rapidly  in  the  early 
stages  of  growth,  a  normal  and  unrestricted  develop- 


FUNCTIONS  OF   THE  NUTRIENTS  159 

ment  demands  an  abundant  supply  of  protein  food.  It 
is  also  true  of  mature  animals  that  sufficient  protein  is 
not  only  necessary  to  health  and  vigor,  but  it  is  essen- 
tial to  production  that  is  satisfactory  in  quantity  and 
quality. 

230.  Protein  as  a  source  of  fats. — The  functions  of 
protein  are  not  restricted,  however,  to  the  use  already 
described,  for  it  is  utilized  in  more  ways  than  any  other 
class  of  nutrients.    It  was  held  at  one  time  that  outside 
the  vegetable  fats  it  is  the  sole  source  of  animal  fats,  and 
this  view  was,  not  so  very  long  ago,  to  some  extent 
accepted.    Indisputable  proof  to  the  contrary  is  now  in 
our  possession.     Certainly  we  must  be  convinced  that 
nitrogen  compounds  of  the  food  are,  with  some  species, 
not  the  most  important  source  of  animal  fat,  for  various 
investigators,  such  as  Lawes  and  Gilbert,  Soxhlet,  and 
others,  have  shown  upon  the  basis  of  searching  experi- 
ments that  sometimes  over  four-fifths  of  the  fat  stored 
by  pigs  must  have  had  its  origin  outside  the  food  protein 
and  fat.    Jordan  showed  that  milk-fat  may  be  largely 
synthesized  from  carbohydrates.    Besides  all  this,  the 
common  experience  of  feeders  that  foods  highly  non- 
nitrogenous   are  often  the  most  efficient  for  fattening 
purposes   is   good  evidence   that  fat   formation   is   not 
greatly  dependent  upon  the  protein  supply.     Neverthe- 
less, the  possibility  of  producing  animal  fat  from  protein 
now  appears  to  be  demonstrated. 

231.  Protein   as   a   source   of   energy. — Protein  can 
unquestionably  serve  as  fuel,  or,  in  other  words,  as  a 
source  of  m  energy.    The  amount  so  used  depends  much 
upon  the  animal  fed  and  the  character  of  the  ration.    In 
the  case  of  a  dog  eating  an  exclusive  meat  diet  or  of  a 
mature  fattening  animal  which  receives  a  ration  liberally 


160  THE  FEEDING  OF  ANIMALS 

nitrogenous,  the  greater  part  of  the  protein  eaten  is  not 
stored  but,  excepting  the  nitrogen  compounds  of  the 
urine,  is  used  as  fuel.  With  milch  cows  or  young  animals 
growing  vigorously  a  much  larger  proportion  escapes 
oxidation.  The  fuel  value  of  protein  will  be  discussed 
later  under  another  head. 

FUNCTIONS  OF  CARBOHYDRATES 

232.  Carbohydrates  the  chief  source  of  energy. — 
Carbohydrates  are  usually  characterized  as  the  fuel  portion 
of  the  food,  or  that  part  which  is  oxidized  to  produce  the 
various  forms  of  energy.  This  conception  of  the  function 
of  these  bodies  is  correct  in  the  sense  that  in  the  case  of 
farm  animals  they  constitute  the  larger  part  of  the  fuel, 
although  not  the  whole  of  it. 

233.  Proportion  of  ration  used  as  fuel. — For  instance, 
in  the  case  of  a  cow  eating  daily  sixteen  pounds  of  diges- 
tible organic  matter,  giving  thirty  pounds  of  milk  con- 
taining 15  per  cent  of  solids,  and  neither  gaining  nor 
losing  flesh,  not  far  from  five  pounds  of  this  organic 
matter  would  be  found  in  the  milk  and  urine,  leaving 
about  eleven  pounds  to  be  used  as  fuel,  about  a  pound 
and  a  half  of  which  might  be  derived  from  the  protein 
and  fat,  the  remainder,  or  nine  and  one-half  pounds,  con- 
sisting of  carbohydrates.  If  a  fattening  steer  were  eating 
the  same  amount  of  the  same  kind  of  food  and  gaining 
two  pounds  of  live  weight  daily,  the  body  increase  and 
urine  would  contain  not  over  two  and  one-half  pounds  of 
dry  matter,  leaving  not  less  than  thirteen  and  one-half 
pounds  to  be  oxidized,  of  which  twelve  pounds  might 
consist  of  carbohydrates  and  fat,  mostly  the  former.  It 
is  clear,  then,  that  while  other  bodies  serve  as  fuel,  the 


FUNCTIONS  OF   THE  NUTRIENTS  161 

carbohydrates  furnish  much  the  larger  part  of  that  which 
is  needed  for  this  purpose. 

234.  Fats   from   carbohydrates. — Contrary    to   views 
that  held  for  a  time,  it  is  now  well  established  that  the 
animal  fats  may  have  their  source  in  the  carbohydrates; 
in  other  words,  starch  and  sugar  and  related  bodies  may 
serve  the  main  purpose  in  feeding  animals  for  fattening. 
In  many  experiments,  notably  those  with  swine,  the  pro- 
tein and  fat  of  the  food  have  fallen  far  short  of  account- 
ing for  the  fat  in  the  body  increase,  sometimes  much  the 
greater  part  of  the  latter  having  no  possible  source  other 
than  the  carbohydrates.    A  practical  expression  of  this 
general   conclusion   concerning  the  fat-forming  function 
of  carbohydrates  is  seen  in  the  well-recognized  value  of 
corn  meal  as  a  fattening  food,  a  feeding-stuff  nearly  seven- 
tenths  of  which  consists  of  starch  and  its  allies.    Experi- 
ments with  milch  cows  leave  no  doubt  that  milk-fat  may 
also  be  derived  from  carbohydrates.    These  more  recent 
views  tend  to  magnify  the  importance  of  the  carbo- 
hydrates as  nutrients. 

FUNCTIONS   OF  THE  FATS  AND   OILS 

235.  Fats  and  carbohydrates  similar  in  function. — 
So  far  as  is  at  present  known,  the  possible  uses  of  the 
food  fats  and  oils  and  of  the  carbohydrates  are  similar. 
In  other  words,  both  may  serve  as  fuel  and  both  may  be 
a  source  of  animal  fat.  The  differences  are  that  the  supply 
of  carbohydrates  is  much  the  larger,  and  the  fuel  value 
of  a  unit  weight  of  fats  is  over  twice  as  great  as  that 
of  starch  and  sugar.    Moreover,  it  seems  possible  for  a 
food  fat  to  become  deposited  as  such  in  the  animal  or 
in  milk  without  essential  change,  whereas  fat  formation 


162  THE  FEEDING  OF  ANIMALS 

from   carbohydrates   involves   complex   chemical   trans- 
formations not  fully  understood. 

FOOD   AS  A  SOURCE   OF   ENERGY 

236.  Work   performed    by    the    animal   organism. — 
The  living  animal,  either  as  a  whole  or  in  some  of  its  parts, 
is  constantly  in  motion.    This  means  that  the  animal 
mechanism  is  ceaselessly  performing  work.    Even  if  the 
body  is    apparently  quiet,   the    heart    beats,   pumping 
blood  to  all  parts  of  the  body,  the  lungs  are  expanded 
and  contracted,  and  the  stomach  and  intestines  keep  up 
the  movements  which  are  essential  to  digestion.   Besides, 
a  living  body  is  the  seat  of  continuous,  invisible  and  com- 
plex chemical  and  physical  changes  that,  if  not  work  in 
the  common  meaning  of  the  term,  are  its  equivalent. 
Walking,    trotting,    pulling,    lifting,    pumping     blood, 
breathing,  masticating,  digesting  and  assimilating  food 
represent,  then,  a  great  variety  of  operations  of  those 
living  machines  which  we  have  named  horse,  ox,  cow, 
and  sheep. 

237.  Work   requires   the    expenditure   of   energy. — 
Now  work  requires   the   expenditure   of  energy.     The 
projection  of  a  rifle  ball  through  space  at  the  rate  of  2,000 
feet  a  second  is  work.   The  ball  does  not  move  of  itself, 
but  is  propelled  by  the  application  of  the  energy  stored  in 
a  powerful  explosive.    Back  of  every  one  of  our  great 
mechanical  operations,  such  as  pumping,  grinding,  and 
moving  railroad  trains,  will  always  be  found  some  sort 
of  energy,  and  what  is  true  of  machinery  made  of  wood 
and  iron  is  equally  true  of  that  made  of  bone  and  muscle. 
The  fact  that  the  mechanism  is  alive  does  not  abrogate 
a  single  physical  law,  so  that  the  fundamental  principles 


FUNCTIONS  OF   THE  NUTRIENTS  163 

of  energy  as  applied  to  machines  are  as  fully  applicable 
to  the  activities  of  animal  life. 

238.  The  animal  organism  does  not  originate  energy. — 
It  is  safe  to  go  farther  and  say  that  the  animal  organism 
does    not    originate    energy.     Among   the   fundamental 
conceptions  upon  which  all  our  knowledge  of  chemical 
and  physical  laws  rests  is  this,  that  energy  and  matter 
are  indestructible,  and,   moreover,  that  the  sum   total 
of  these  in  the  universe  is  unchangeable.    If,  then,  the 
horse  expends  the  muscular  energy  necessary  to  draw  a 
load  of  one  ton  over  10  miles  of  road,  the  equivalent  of 
this  must  have  been  supplied  to  his  body  from  some  out- 
side source.    He  could  not  create  it.    We  know  that  this 
is  so,  and  we  also  know  it  is  conveyed  to  the  animal 
in  the  food. 

239.  The  nature  of  energy. — A  definition  of  energy  is 
difficult.    It  can  be  illustrated  by  pointing  out  some  of 
its  manifestations.    It  is  a  common  observation  to  see  a 
blacksmith  hammer  an  iron  rod  until  it  is  red  hot.  The 
motion  of  the  hammer-head  descending  with  great  veloc- 
ity was  suddenly  arrested  when  it  came  in  contact  with 
the  rod.    The  hammer-head  was  driven  by  energy  sup- 
plied from  two  sources,  gravity  or  the  energy  of  position, 
and  energy  exerted  through  the  blacksmith's  arm,  that 
is,  energy  supplied  through  oxidation  in  the  blacksmith's 
body.   When  the  hammer  met  the  iron  rod  on  the  anvil, 
the  mass  motion  ceased.    The  operating  energy  was  not 
annihilated,  but  it  appeared  in  another  form.  The  motion 
of  the  hammer-head  (kinetic  energy),  a  mass  of  matter, 
was  communicated  to  the  molecules  of  the  iron  rod,  and 
as  the  vibrations  of  the  molecules  increased  in  rapidity, 
the  rod  grew  hotter  and  hotter.    Here  we  have  another 
manifestation  of  energy,  viz.,  the  motion  of  the  molecule. 


164  THE  FEEDING  OF  ANIMALS 

The  iron  rod  might  have  been  heated  in  another  way — 
by  plunging  it  into  burning  charcoal.  Somehow,  when  it 
is  deposited  in  the  plant,  there  becomes  stored  in  this 
carbon,  in  a  way  about  which  we  can  only  theorize,  what 
we  may  call  chemical  energy,  which,  when  combustion 
occurs,  is  changed  into  heat  or  molecular  motion.  From 
these  phenomena  we  learn  that  not  only  are  there  several 
manifestations  of  energy,  but  that  one  manifestation  is 
transferable  into  another. 

240.  Transformations  of  energy  through  the  use  of 
machinery. — Perhaps  another  illustration  may  still  fur- 
ther serve  our  purpose.    A  small  dynamo  is  being  run 
by  a  pair  of  horses  working  in  a  tread-power  such  as  is 
used   for  threshing   grain.     The  horses   are   constantly 
climbing  up  a  moving  treadway  and  thereby  communi- 
cating motion  to  machinery.    The  energy  thus  applied 
is  the  result  of  combustion  in  the  body  of  the  horse.  This 
motion,  is,  by  the  dynamo,  converted   into  electricity, 
which,  by  passing  through  the  carbon  film  of  an  incandes- 
cent lamp  and  there  meeting  resistance,  is  in  part,  at 
least,  manifested  as  heat.     We  have,  then,  in  a  chain, 
muscular  effort,  motion  of  the  mass  (pulleys  and  wheels), 
electricity,  and  heat,  all  manifestations  of  energy  and 
all  transferable  one  into  the  other. 

241.  The  horse  a  machine. — This  is  a  fairly  good  pic- 
ture of  what  goes  on  with  the  horse  himself,  externally 
and  internally,  in  sustaining  life  and  performing  labor 
for  his  owner.   It  is  now  known  that  through  the  combus- 
tion of  the  carbon  compounds  of  vegetable  and  animal 
origin,  which  serve  as  nutrients,  chemical  energy  may  be 
transformed  into  those  other  forms  that  are  manifested  in 
the  activities  of  living  beings,  and  it  is  a  notable  triumph 
of  science  to  be  able  to  declare  with  certainty  that  the 


FUNCTIONS  OF   THE  NUTRIENTS  165 

ceaseless  and  multiple  activities  of  life  on  this  planet  are 
sustained  by  an  energy  which  comes  to  the  plant  in  the 
sun's  rays  and  is  stored  there  through  the  synthesis  of 
carbon  compounds. 

242.  Measurement  of  energy. — It  is  obvious  that  if 
the  internal  and  external  work  performed  by  the  animal 
is  sustained  by  the  food,  it  is  desirable  to  measure  the 
energy   available    in    different    feeding-stuffs,    provided, 
of  course,  that  they  differ  in  this  respect.    In  order  to 
measure  anything,  we  must  have  a  standard  or  unit  of 
measurement.    In  this  case  it  cannot  be  a  unit  of  space 
or  of  mass,  that  is,  we  cannot  declare  that  corn  meal  con- 
tains so  many  cubic  feet  or  pounds  of  available  energy. 
Energy  has  neither  dimensions  nor  weight.    If  we  meas- 
ure it  at  all,  it  must  be  by  units  of  temperature  or  of  work 
performed.   Units  of  this  latter  kind  are  the  ones  applied 
to  the  measurement  of  food  energy.    The  one  that  has 
been  most  commonly  used  is  the  Calorie,  this  being  the 
energy  which  in  terms  of  heat  is  sufficient  to  raise  the 
temperature  of  one  pound  of  water  4°  F.    Expressed  in 
terms  of  work,  the  Calorie  (large)  is  very  nearly  1.53 
foot-tons,  or  in  other  words,  it  is  equivalent  to  the  work 
involved   in  lifting  one  ton  1.53  feet.     Heat  units  are 
expressed  in  both  the  large  Calorie  and  the  small  calorie. 
When  the  former  is  indicated,  the  word  begins  with  a 
capital   letter.     The   Calorie   represents    1,000   calories. 
Armsby  proposes  the  use  of  the  term  therm,  which  repre- 
sents 1,000  Calories,  which  renders  less  cumbersome  the 
figures  given  for  the  energy  of  a  ration. 

243.  Determination  of  energy  units  in  feeding-stuffs. — 
The  total  energy  or  heat  units  developed  in  the  combus- 
tion  of    feeding-stuffs    is  determined    in  an  apparatus 
called  a  calorimeter.   The  latest  form  of  this  device  is  one 


166  THE  FEEDING  OF  ANIMALS 

in  which  the  ground  hay  is  burned  under  pressure  in  the 
presence  of  pure  oxygen,  and  the  heat  evolved  is  all 
used  in  warming  a  known  weight  of  water.  Data  are  thus 
obtained  from  which  it  is  possible  to  calculate  the  Calories 
in  the  particular  material  burned.  The  energy  value  of 
single  compounds,  such  as  albumin,  starch,  and  sugar, 
may  also  be  found  in  the  same  way,  as  has  been  done  in 
a  large  number  of  instances.  These  data  show  that  the 
heat  resulting  from  the  combustion  of  the  compounds  of 
a  given  class  is  not  the  same  in  all  cases.  The  value  in 
large  Calories  of  one  gram  of  several  pure  nutrients  is 
shown  in  the  following  table: 


TABLE  XXVIII 

PROTEINS 

Calories 

Calories 

Wheat  gluten  .    .    . 

5.99          Egg  albumin    .... 

5.73 

Gliadin  

;'  ",'•      5.92          Muscle  (pure)  .... 

5.72 

Glutenin   .    . 

f.,'.     5.88          Blood  fibrin      .... 

5.64 

Plant  fibrin       .    .    , 

,    ,       5.94          Peptone    

5.30 

Serum  albumin     . 

.    .   .  5.92          Wool  

5.51 

Milk  casein       .    . 

5.86          Gelatin      

5.27 

Yolk  of  egg      .    . 

,    .       5.84         Asparagin  (amide) 

3.45 

CARBOHYDB 

.ATES                                         FATS 

Calories 

Calories 

Starch   

,-  .       4.18          Of  swine    

9.38 

CeUulose   ...... 

,    .       4.18          Of  oxen     

9.38 

Glucose     .... 

,  '.       3.74          Of  sheep    

9.41 

Cane-sugar   ... 

ki  .       3.95          Maize  oil      

9.28 

Milk-sugar        .    .  * 

,v..'  '  3.95          Olive  oil    

9.47 

Maltose     .    . 

,    .       3.95          Ether-extract  of  oats  . 

8.93 

Zylose    ;    .    .    .    . 

.   .      3.74          Ether-extract  of  barley 

9.07 

The  heat  values  of  a  gram  of  the  dry  substance  of 
various  cattle  foods,  which  is  a  mixture  of  the  several 
nutrients,  were  found  by  recent  determinations  to  be  the 
following,  expressed  in  calories: 


FUNCTIONS   OF    THE  NUTRIENTS  167 

TABLE  XXIX 

Calories  Calories 

Mixed  hay 4.39  Corn  meal 4.47 

Alfalfa  hay 4.40  Linseed  meal    ....  5.04 

Oat  straw 4.48  Flaxseed  meal  ....  6.93 

Sugar-beets      ....       3.93  Rice  meal 4.40 

These  figures  mean  that  when  a  gram  of  each  of 
these  materials  is  wholly  burned  the  heat  produced 
is  as  stated. 

244.  Metabolizable    energy. — We    must    distinguish, 
however,   between  the  heat  produced  when  any  food 
substance  is  wholly  oxidized  in  a  calorimeter  and  the  heat 
or  energy  which  is  available  (metabolizable)  when  the 
same  material  is  applied  to  physiological  uses.    It  never 
happens  that  the   combustible  portion  of  a  ration  is 
entirely  oxidized  in  the  animal. 

245.  Loss  of  food  energy  in  feces. — In  the  first  place, 
the  food  of  domestic  animals  is  practically  never  all 
digested   and,   as   only   the   digested   portion   furnishes 
energy,  the  available  fuel  value  of  a  ration  must  be  based 
primarily,  not  on  the  total  quantity  of  dry  matter  it 
represents,  but  on  the  amount  which  is  dissolved  and 
passes  into  the  blood.    If  all  feeding-stuffs  or  rations 
were  digested  in  the  same  proportion  and  with  the  same 
ease,  then*  total  fuel  values  might  show  their  relative 
energy  worth,  but  as  digestion  coefficients  for  dry  matter 
vary  from  less  than  50  per  cent  with  the  straws  to  nearly 
90  per  cent  with  some  of  the  cereal  products,  it  is  evident 
that  the  fuel  waste  in  the  feces  is  not  uniform. 

246.  Loss  of  food  energy  in  urine. — In  the  second 
place,  the  digested  proteins  are  never  fully  burned.    A 
portion  of  these  compounds  always  passes  off  in  the  urine 
unoxidized,  the  fuel  value  of  which  is  lost  to  the  animal. 


168  THE  FEEDING  OF  ANIMALS 

For  this  reason  the  available  energy  of  the  digested  pro- 
teins is  about  one-fourth  less  than  the  total. 

247.  Loss  of  food  energy  in  gases. — In  the  third  place, 
there  is,  with  ruminants  and  horses  at  least,  an  escape 
from  the  alimentary  canal  of  unconsumed  gases,  due  to 
the   fermentations   which   take   place   during   digestion. 
These  gases,  mostly  methane   (marsh  gas)   with  some 
carbon  dioxid  and  from  green  leguminous  plants  some 
hydrogen  sulfide  and  nitrogen,  have  their  source  in  the 
carbohydrates  and  crude  fiber,  and  Kellner  found  them 
to  represent  from  10  to  20  per  cent  of  the  total  energy 
value  of  the  dry  substance  digested  from  various  materials. 
From  twenty  experiments,  upon  five  different  animals, 
Kuhn  found  the  loss  in  methane  to  be  over  one-seventh 
the  energy  of  the  digested  crude  fiber  and  nitrogen-free 
extract. 

248.  Recent  determinations  of  metabolizable  energy. 
— The  most  accurate  and  extensive  determinations  of 
metabolizable  energy  that  have  been  made  in  this  coun- 
try, or  perhaps  anywhere,  are  the  result  of  recent  inves- 
tigations by  Armsby  and  Fries  with  the  aid  of  a  respira- 
tion calorimeter.    These  involved  analysis  of  the  feeds 
used  and  determinations  of  the  total  energy  of  the  feeds 
and  of  the  losses  through  the  various  avenues  indicated 
above.    In  carrying  on  this  work,  nine  steers  were  used, 
involving  3,401  experiments.    Without  giving  any  atten- 
tion to  the  technics  of  the  work,  which  required  a  costly 
and   extensive  equipment  of  men   and   apparatus   and 
involved   thousands   of   accurate   chemical   analyses   of 
foods  and  the  different  forms  of  excreta,  the  following  may 
be  cited  as  an  example  of  the  necessary  computation  of 
losses  of  chemical   energy  from  a  ration  through  the 
excreta  and  the  methane: 


FUNCTIONS  OF   THE  NUTRIENTS 


169 


TABLE  XXX 

Period  2       Period  3 
Calories        Calories 

Total  energy  of  feed — 

Timothy  hay 12,477       12,618 

Grain  mixture,  No.  1 12,549 


Total 25,026      12,618 


Energy  of  excreta  — 
Feces   
Urine  
Methane     

7,371 
1,536 
2098 

5,247 
627 
1  057 

Total  

11  005 

6931 

Metabolizable  energy   . 

.  14.021 

5.687 

The  above  computation  is  for  a  mixed  ration  contain- 
ing both  coarse  fodder  and  grain.  In  order  to  ascertain 
the  losses  from  the  grain  itself,  those  for  the  hay  having 
been  determined  by  other  experiments,  the  following 
computation  was  necessary: 


TABLE  XXXI 


Chemical 
energy 
of  feed 

Chemical  energy  of  excreta 

Metabo- 
lizable 
energy 

Feces 

Urine 

Methane 

Total  ration  
Computed  for  hay    .    . 

Grain  mixture  by  dif- 
ference   .    .    . 

Calories 

25,026 
12,477 

Calories 

7,371 
5,254 

Calories 

1,536 
591 

Calories 
2,098 

1,003 

Calories 

14,021 
5,629 

12,549 

2,117 

945 

1,095 

8,392 

249.  Distribution  of  losses  of  food  energy. — In  the 
next  table  there  are  given  for  eight  individual  feeding- 
stuffs  and  several  mixed  rations  and  grain  mixtures  the 
percentage  of  losses  through  the  different  avenues  and 


170 


THE  FEEDING  OF  ANIMALS 


the  percentage  of  metabolizable  energy,  or  in  other  words, 
that  which  may  be  applied  to  use  by  the  animal,  from  the 
several  materials  involved  in  the  experiments: 

TABLE  XXXII. 


Pera 

jntage  1 

jsses 

Percentage 
metabol- 

In 

feces 

In 

urine 

In 
CH4 

izable 
energy 

Timothy  hay  

48.13 

3.57 

6.94 

41.36 

Red  clover  hay    ....":  *i    .    .    .    .    . 
Mixed  hay    
Alfalfa  hay           .        .    .    \      .-      . 

40.95 
43.92 
47.54 

6.82 
5.17 
5.58 

5.95 
7.35 
594 

46.28 
43.56 
4094 

Alfalfa  meal      .....    ,~;  .    . 
Maize  stover     .    .    ...    .    .  .;    .    . 
Maize  meal  .    .    .    .    .    .    .  *  .    ',    . 
Wheat  bran      .......    .    .\. 
Grain  mixture,  No.  1  .        ...    .  v 

42.01 
42.82 
14.74 
31.77 
17.91 

5.89 
4.24 
3.32 
5.38 
720 

6.11 
7.88 
9.75 
7.44 

784 

45.99 
45.06 
72.19 
55.41 
6705 

Grain  mixture,  No.  2  .    .    .    .    «    .  -.  - 

22.03 

4.54 

9.06 

64.37 

Hominy  chop   .    . 

1215 

384 

920 

7481 

Alfalfa  hay  and  grain  mixture,  No.  2. 
Mixed  hay  and  maize  meal    .    .    .  •  .' 
Mixed  hay  and  hominy  chop     .    .    . 

30.27 
24.22 
28.02 

4.83 
3.87 
4.44 

7.98 
8.89 
8.15 

56.92 
63.02 
59.39 

It  will  be  noted  that  the  main  loss  is  by  way  of  the 
undigested  food  residue.  The  energy  loss  in  the  urine 
ranged  from  3.3  to  7.2  per  cent.  The  loss  from  methane 
ranged  from  5.9  to  9.7  per  cent  of  the  total  dry  matter, 
or  from  4.2  to  5.1  "grams  to  100  grams  of  digestible  car- 
bohydrates, the  average  being  4.8  grams.  Kellner  found 
4.2  grams,  and  these  figures  may  be  taken  as  a  basis  for 
the  estimate  of  the  probable  loss  of  chemical  energy 
through  fermentations.  The  undigested  residue  varies 
greatly  according  to  the  nature  of  the  food.  These  authors 
have  investigated  the  influence  of  the  quantity  of  the 
ration  upon  the  losses  of  chemical  energy. 


FUNCTIONS  OF   THE  NUTRIENTS  171 

250.  Influence  of  size  of  ration  on  losses  of  methane. — 

The  losses  through  gas  evolution  were  found  to  be  greater 
in  twenty-nine  cases  out  of  thirty-one  with  the  lighter 
ration  and  tended  to  be  somewhat  greater  on  the  mixed 
ration  with  a  very  much  larger  proportion  of  readily 
soluble  carbohydrates.  This  simply  means  that  the 
"bacterial  fermentation  of  the  carbohydrates  in  the  di- 
gestive tract  of  cattle  proceeds  to  a  distinctly  greater 
extent  on  light  than  on  heavy  rations." 

251.  Influence  of  size  of  ration  on  losses  in  the  un- 
digested residue. — As  is  well  known,  this  loss  will  be  by 
no  means  uniform  as  this  residue  is  proportionately  much 
larger  with  coarse  foods  than  with  grain  foods.    In  these 
comparisons  there  seemed  to  be  practically  no  difference  in 
the  proportion  of  loss  as  between  heavy  and  light  rations, 
these  results  not  agreeing  with  former  observations. 

252.  Influence  of  individuality  on  energy  losses. — 
Comparison  was  made  between  a  pure-bred  Shorthorn 
steer  and  a  so-called  scrub.    Practically  no  difference  in 
the  loss  of  chemical  energy  was  discovered  as  between 
these  two  animals. 

253.  Estimates  of  metabolizable  energy  on  the  basis 
of  digestible  organic  matter. — It  is  discovered  that  the 
metabolizable  energy  in    a    unit    of    digestible  organic 
matter  is  fairly  uniform  as  between  the  different  coarse 
fodders  on  the  one  hand  and  the  various  concentrates 
on  the  other.    Various  investigators  have  studied  this 
question  and  their  results  show  a  satisfactory  agreement. 
It  appears  that  the  metabolizable  energy  which  may  be 
derived  from  the  several  feeding-stuffs  will  vary  quite 
directly  with  the  proportion  of  digestible  dry  matter. 
The  following  table  shows  the  figures  reached  by  several 
investigators : 


172  THE  FEEDING  OF  ANIMALS 

TABLE  XXXIII. 
Coarse  Feeds 

_,  .  Therms 

Armsby  and  Fries:  per  kilo 

Timothy  hay    .    ,...'..., 3.49 

Red  clover  hay 3.49 

Mixed  hay 3.39 

Alfalfa  hay  and  meal 3.61 

Maize  stover 3.45 

Average 3.48 

Kellner  and  Kohler: 

Meadow  hay 3.50 

Oat  straw     3.74 

Wheat  straw 3.31 

Extracted  straw       ...  3.64 

Average 3.55 

Concentrates 
Armsby  and  Fries: 

Maize  meal       3.80 

Wheat  bran 3.99 

Gram  mixture,  No.  2 3.88 


Average 3.89 

Grain  mixture,  No.  1 , 3.91 

Hominy  chop /.    .  *-.    .    .    .       4.08 

Average >   •'  • 4.00 

Kellner  and  Kohler: 

Beet  molasses 3.47 

Starch        V 3.60 

Wheat  gluten   .    ...    ..-..• 4.79 

It  is  self-evident,  of  course,  that  the  metabolizable 
energy  will  be  greatly  influenced  by  the  percentage  of  fat 
or  oil  in  a  ration,  as  the  fats  have  more  than  double  the 
energy  value  of  the  carbohydrates. 


FUNCTIONS  OF   THE  NUTRIENTS 


173 


254.  Comparison  of  metabolizable  energy  in  coarse 
fodders  and  grains. — The  following  table  selected  from 
the  data  of  the  same  authors  admits  of  a  direct  com- 
parison of  the  proportions  of  metabolizable  energy  in 
coarse  fodders  and  grains. 


TABLE  XXXIV 
Coarse  Foods 


Gross 
energy  per 
kilo  dry 
matter 

Losses 
energy  per 
kilo  dry 
matter 

Metabolizable  energy 

Per  kilo 
dry 
matter 

Per  kilo 
digestible 
organic 
matter 

Timothy  hay  .  
Red  clover  hay   
Mixed  hay  
Alfalfa  hay  and  meal     .    . 
Maize  stover   

Average 

Therms 

4.51 
4.46 
4.39 
4.37 
4.33 

Therms 

2.66 
2.46 
2.48 
2.45 
2.38 

Therms 

1.85 
2.00 
1.91 
1.91 
1.95 

Therms 

3.49 
3.49 
3.39 
3.60 
3.45 

4.41 

2.49 

1.92 

3.48 

These  data  show  that  approximately  56  per  cent  of  the 
gross  energy  of  the  dry  matter  fed  in  coarse  fodders  is 
lost  in  the  feces,  urine,  and  gases  evolved. 

Grains 


Gross 
energy  per 
kilo  dry 
matter 

Losses 
energy  per 
kilo  dry 
matter 

Metabolizable  energy 

Per  kilo 
dry 
matter 

Per  kilo 
digestible 
organic 
matter 

Maize  meal      
Wheat  bran     ...... 
Hominy  chop      

Average    

Therms 

4.44 
4.53 
4.71 

Therms 
1.11 

2.02 
1.19 

Therms 
3.33 
2.51 
3.52 

Therms 

3.80 
3.95 
4.07 

4.56 

1.44 

3.12 

3.94 

174  THE  FEEDING  OF  ANIMALS 

The  loss  from  the  grains  is  relatively  much  less  than 
from  the  coarse  fodders,  being  only  an  average  of  31.5 
per  cent.  This  is  easily  accounted  for  by  the  greater 
digestibility  of  the  grains. 

We  are  to  understand,  then,  that  the  metabolizable 
energy  of  a  ration  is  represented  by  the  fuel  value  of  the 
dry  matter  which  is  digested  from  it,  minus  the  dry  mat- 
ter of  the  urine  and  that  lost  in  gases. 

If,  however,  we  wish  to  know  the  actual  energy  gain 
to  the  animal  from  a  particular  ration,  we  must  go  farther 
than  a  determination  of  its  available  energy. 

255.  Net  energy. — Within  a  comparatively  short  time 
we  have  begun  to  speak  of  the  net  energy  of  foods,  and  as 
this  is  a  practical  consideration  which  is  likely  to  be  the 
subject  of  much  future  discussion,  it  is  well  to  notice  it 
in  an  explanatory  way.    As  we  have  learned,  food  is  not 
applied  to  use  until  it  reaches  the  blood.    Between  the 
time  when  it  is  taken  into  the  mouth  and  when  it  passes 
into  the  circulation,  it  must  have  work  expended  on  it 
in  the  way  of  mastication,  solution,  moving  it  along  the 
digestive  tract  and  assimilation,  and  it  seems  probable 
that  the  amount  of  this  work  for  a  pound  of  food  must 
vary  greatly  in  different  cases.   In  fact,  this  seemed  to  be 
proven  by  the  result  of  some  masterly  investigations  con- 
ducted by  Zuntz  and  associates  in  Germany. 

256.  Work  of  mastication  (Zuntz), — Zuntz  determined 
the  oxygen  consumption,  that  is,  increased  energy  used, 
during  the  mastication  of  several  feeds  by  a  horse  as 
compared  with  what  occurred  with  the  animal  at  rest. 
In  considering  the  data  shown  in  Table  XXXV  it  should 
be  remembered  that  mastication  is  only  one  factor  of  the 
loss  of  energy  involved  in  the  appropriation  of  food,  and 
perhaps  a  minor  one. 


FUNCTIONS   OF   THE  NUTRIENTS 


175 


TABLE  XXXV 


Feed 

Number 
of 
experi- 
ments 

Additional 
oxygen 
con- 
sumed 

Additional 
CO, 
excreted 

Equivalent 
energy 

Oats  and  cut  straw  (6:1) 
Hay     
Hay,  oats,  and  cut  straw 
Maize  and  cut  straw  (6:1)    . 
Green  alfalfa      

8 
8 
8 
2 

7 

Liters 

12.964 
33.840 
20.072 
7.133 
6.171 

Liters 

10.679 
27.813 
17.677 
6.205 
4.980 

Calories 
64.17 
167.44 
100.79 
35.72 
30.42 

Computed  for  oats  alone 
Computed  for  maize  alone   . 

47.00 
13.80 

257.  Difference  in  total  energy  use  with  different 
rations. — Zuntz  and  Hagemann  determined  the  oxygen 
use  and  carbon  dioxid  excretion  during  an  exclusive  hay 
diet  as  compared  with  a  diet  of  mixed  hay  and  grain. 

TABLE  XXXVI 


Hay 

Hay. 
and  grain 

Time  since  last  fed                               hours 

26 

28 

Ration  — 
Hay       ...                          .            kilos 

About  10.5 

4,75 

Oats      kilos 
Straw                                                    kilos 

6. 
1. 

Total  digested  nutrients  (fat  x  2.4)  grams 

Per  kilogram  and  minute  — 
Oxygen  consumed       ....    cub.  cent. 
Carbon  dioxid  given  off     .    .    cub.  cent. 
Energy  set  free  (computed)      .  gr.  Cals. 
Energy  katabolism  per  day  and  head 
Calories 

4,125 

3.9837 
3.6586 
19.552 

12,450 

5,697 

3.6986 
3.6695 
18.339 

11,678 

The  comparison  of  the  energy  use  for  the  consump- 
tion of  the  exclusive  hay  ration  and  hay-and-grain  ration 
shows  that  the  latter,  carrying  5,697  grams  of  digesti- 


176  THE  FEEDING  OF  ANIMALS 

ble  matter,  used  1,213  gram-calories  less  energy  than  the 
exclusive  hay  ration,  carrying  4,125  grams  of  digestible 
matter.  The  hay  ration  cost  for  consumption  4.7  Calories 
per  gram  of  digestible  dry  matter  and  the  mixed  ration 
only  3.2  Calories.  This  increased  use  of  energy  can  only 
be  explained  by  assuming  that  the  cost  of  consuming  the 
grain  was  proportionately  less  than  that  of  the  hay,  a 
difference  presumably  due  to  the  greater  cost  of  masti- 
cating the  hay. 

The  differences  revealed  by  Kuntz's  figures  are  inter- 
esting and  important.  Chewing  green  food  cost  in  labor 
only  about  18  per  cent  of  the  effort  required  to  masti- 
cate its  equivalent  of  dry  hay,  the  proportions  of  labor 
for  hay,  oats,  and  corn  being  in  the  ratio  of  100,  28 
and  8J^. 

This  author  goes  farther  and  calculates  that  the 
work  of  mastication  and  digestion  combined  is  48  per 
cent  of  the  energy  value  of  the  digested  material  from  hay 
and  19.7  per  cent  of  that  from  oats.  He  also  makes  the 
statement  that  in  general  the  coarse  foods  have  20  per 
cent  less  net  energy  value  than  the  grains.  All  these 
deductions  are  based  upon  the  excess  of  oxygen  used  by 
the  animal  when  engaged  in  the  work  of  chewing  and 
digestion,  over  that  used  when  at  rest.  It  would  follow 
from  these  results  that  anything  in  the  way  of  growth  or 
treatment  of  a  fodder  which  tends  to  toughen  or  harden 
the  tissue  reduces  the  net  energy  value. 

258.  The  work  of  digestion.— Armsby  regards  the 
work  of  digestion  outside  of  mastication  as  a  small  factor. 
His  experiments  when  he  attempted  to  measure  the  work 
of  mastication  by  the  increased  heat  elimination,  showed 
no  distinct  evidence  of  such  increase.  He  concludes  that 
there  must  have  been  an  increased  production  of  heat 


FUNCTIONS  OF   THE   NUTRIENTS 


177 


during  mastication  which  was  not  given  off  promptly. 
The  Zuntz  method  of  measuring  the  increase  of  oxygen 
consumption  would  seem  to  be  the  more  reliable. 

The  results  of  Kellner  and  of  Armsby  and  Fries,  which 
follow,  do  not  appear  to  ratify  the  conclusions  of  Zuntz 
and  Hagemann,  although  the  work  of  mastication  was  not 
determined  as  a  separate  factor. 

259.  Total  energy  expended  in  feed  consumption. — 
Extensive  determinations  of  the  total  energy  expended 
in  feed  consumption  have  been  made,  both  by  Kellner 
and  by  Armsby  and  Fries.  The  use  of  energy  in  this  direc- 
tion is  determined  by  comparing  the  heat  production  of 
two  rations  of  unlike  quantity,  heat  production  being 
equivalent  to  the  energy  expenditure  by  the  animal. 
The  increased  heat  production  for  the  larger  ration  should 
be  credited,  therefore,  to  the  increase  of  material  in  the 
ration,  whether  a  single  feed  or  a  mixture  of  feeds. 
Results  by  Armsby  and  Fries  follow: 

TABLE  XXXVII 


Quantity 
of  dry 
matter 
eaten 

Total 
heat 
produc- 
tion 

Distribution  of  heat  production 

Stand- 
ing 

Rising 
and 
lying 
down 

Fer- 
menta- 
tion 

Re- 
main- 
der 

Period  4      
Periods      
Difference       .... 
Difference    per    kilo- 
gram of  dry  matter 

Grams 

4,892 
2,974 

Cals. 

9,523 
7,791 

Cals. 

'1,438 
1,107 

Cals. 

59 

40 

Cals. 

794 

498 

Cals. 

7,232 
6,146 

1,918 

1,732 
903 

331 
173 

19 
9 

296 
154 

1,086 
567 

The  "remainder,"  after  deducting  from  the  total 
heat  production  that  caused  by  standing,  rising,  lying 

NOTE. — In  a  recent  publication  by  Armsby  (Pennsylvania  State 
College  Bulletin  No.  142)  the  position  is  emphatically  taken  that  the 
consumption  cost  with  concentrates  is  as  great  as  with  coarse  feeds,  and 
suggests  other  factors  which  obscure  differences  caused  by  unlike 
mechanical  work. 


178 


THE  FEEDING  OF  ANIMALS 


down,  and  fermentation,  is  that  which  should  be  charged 
to  the  work  of  consumption.  As  the  smaller  ration  was 
less  than  the  other  by  1,918  grams  and  the  heat  produc- 
tion was  1,086  Calories  less  for  the  smaller  ration,  it 
appears  that  the  work  of  consumption  was  567  Calories 
to  a  kilo  of  dry  matter  or  258  Calories  to  a  pound. 

260.  Calculation  of  net  energy  value. — The  following  is 
an  example  of  the  calculation  of  net  energy  value: 


TABLE  XXXVIII 

Calories 

Total  chemical  energy 

Losses  of  chemical  energy    .... 

Infeces 2,062 

In  urine       243 

In  methane  ....        266 


Calories 


Calories 
4,408 


Total 

Increased  heat  production 


2,571 
1,202 


Total  losses 3,773 

Net  energy  value       635 

261.  Net  energy  of  various  feeds. — In  this  way  the 
following  table  was  derived  from  the  data  secured  by 

Armsby  and  Fries: 

TABLE  XXXIX 


Feeding-stuff 

Gross 
energy 

Losses  of 
chemical 
energy 

Energy 
expended 
in  feed 
consump- 
tion 

Net 
energy 
values 

Timothy  hay     ...    .    . 
Red  clover  hay    •>.    .    .    . 
*Alfalfahay     .    .    .    .,'..    . 
Maize  stover      .    .    ... 
Maize  meal    .    ...    .    . 
Wheat  bran                      .  ' 

Per  kilo 
Calories 
4,518 

4,462 
4,372 
4,332 
4,442 
4532 

Per  kilo 
Calories 

2,664 
2,461 
2,451 
2,380 
1,115 
2,021 

Per  kilo 
Calories 

782 
962 
1,169 
1,065 
1,434 
1,177 

Per  kilo 
Calories 

1,072 
1.039 
752 
887 
1,893 
1,334 

Grain  mixture,  No.  1    .    . 
Hominy  chop     .    .    .       ;;•• 

4,685 
4,709 

1,621 
1,187 

1,327 
1,365 

1,737 
2,157 

*Includes  alfalfa  meal. 


FUNCTIONS   OF   THE  NUTRIENTS 


179 


The  values  arrived  at  by  Kellner  are  in  the  next  table. 
These  differ,  as  would  be  expected,  somewhat  from  the 
values  reached  by  Armsby  and  Fries  because  of  a  dif- 
ference in  the  character  of  the  materials  fed. 

TABLE  XL 


Feeding-stuff 

Gross 
energy 

Losses  of 
chemical 
energy 

Energy 
expended 
in  feed 
consump- 
tion 

Net 
energy 
values 

Meadow  hay 

Per  kilo 
Calories 

4433 

Per  kilo 
Calories 

2,260 

Per  kilo 
Calories 

1,254 

Per  kilo 
Calories 

919 

Oat  straw     
Wheat  straw  
Extracted  straw      .... 
"Grass  hay"     .    .    .    .    .  Y 
Rowen                 .  \    . 

4,436 

4,444 
4,147 

2,848 
3,062 
1,013 

1,014 
1,138 
1,160 
1,045 
958 

574 
244 
1,974 
803 

747 

Barley  straw  .  .  --:  .  .  .-  . 
Clover  hay  
Starch  
Peanut  oil  
Wheat  gluten  
Beet  molasses  

4,152 
9,457 
5,579 
3,743 

1,101 
4,165 
1,974 
945 

877 
932 
1,248 
1,727 
2,096 
988 

747 
811 
1,803 
3,565 
1,509 
1,810 

262.  Computing  net  energy  values  of  feeding-stuffs. — 
It  is  very  evident  that  it  is  not  possible  to  make  direct 
determinations  of  the  net  energy  values  of  all  feeding- 
stuffs,  but  these  may  be  estimated  with  reasonable 
accuracy.  The  following  method  of  computing  these 
estimates  may  be  followed,  which  is  based  on  the  total 
digestible  material,  and  the  conclusion  that  each  gram 
of  digestible  organic  matter  contains  3.5  calories  of 
metabolizable  energy.  The  energy  used  for  feed  con- 
sumption is  reduced  to  the  percentage  of  dry  matter  in 
the  three  feeds  entering  into  the  computation  shown  in 
Table  XLI. 


180 


THE  FEEDING  OF  ANIMALS 
TABLE  XLI 


Alfalfa 
hay 

Oat 
straw 

Wheat 
bran 

Total  dry  matter             

Per  cent 

91.6 

Per  cent 
90.8 

Per  cent 

88.5 

Digestible  — 
Protein                              

10.58 

1.2 

12.01 

Carbohydrates 

37.33 

38.64 

41.23 

Fats           

1.38 

.76 

2.87 

Total  digestible    

49.29 

40.6 

56.11 

Alfalfa  hay,    1,169   calories   X    91.6    per  cent  dry  matter =1,071 

calories  per  kilogram  air-dry  feed. 
Oat  straw,  1,014  calories  X  90.8  per  cent  dry  matter=921  calories 

per  kilogram  air-dry  feed. 
Wheat  bran,   1,138  calories  X  88.5  per  cent  dry  matter =1,007 

calories  per  kilogram  air-dry  feed. 

Alfalfa  hay  (3.5  calories  X  492.9  grams   digestible  matter) — 1,071 

calories =654    calories    per    kilogram =29.7  therms    per    100 

pounds  air-dry  feed. 
Oat  straw  (3.5  calories  X  406  grams  digestible  matter) — 921 

calories =500   calories    per    kilogram =22.7   therms   per    100 

pounds  air-dry  feed. 
Wheat  bran  (3.9  calories  X  561.1  grams  digestible  matter)— 1,007 

calories =1,181  calories  per  kilogram =53.6  therms    per    100 

pounds  air-dry  feed. 

These  methods  of  ascertaining  net  values  of  feeds  may 
be  regarded  as  complex,  but  they  are  unquestionably 
the  most  accurate  of  any  methods  so  far  developed. 

The  results  of  Armsby  and  Fries  and  Kellner  do  not 
accord  with  a  somewhat  widespread  teaching  that  the 
energy  expended  in  the  consumption  of  coarse  feeds  is 
greatly  more  for  a  unit  of  dry  matter  than  is  the  case  with 
the  concentrates.  It  is  conceded,  of  course,  that  the 
energy  expended  in  the  mechanical  work  of  mastication 
must  be  greater  in  the  coarse  foods  than  in  the  grain 


FUNCTIONS  OF   THE  NUTRIENTS  181 

feeds.  It  seems,  from  the  later  determinations,  however, 
that  when  all  factors  are  considered,  the  difference  in  the 
total  energy  expenditure  in  the  two  classes  of  feeds  is  not 
greatly  unlike. 

263.  Estimation  of  production  values  proposed  by 
Armsby. — Instead  of  using  net  or  production  values  as 
experimentally  determined  for  each  individual  feed, 
Armsby  has  computed  a  table  based  largely  on  the 
results  of  investigations  by  Kellner. 

This  investigator  arrived  at  what  is  termed  the  pro- 
duction values  of  pure  nutrients,  such  as  a  single  pro- 
tein, starch,  or  one  of  the  fats.  His  figures  are  as  follows: 


TABLE  XLII.    PRODUCTION  VALUES  PER  POUND 

Calories 

Digestible  proteins 1016 

Digestible  starch  or  crude  fiber      1071 

Digestible  cane-sugar       812 

Digestible  fat — 

In  coarse  fodders  and  roots 2041 

In  grains  and  by-products 2273 

In  feeds  with  over  5  per  cent  fat 2585 


In  making  up  the  tables  of  production  values,  these 
values  for  pure  nutrients  are  used  in  connection  with  a 
given  allowance  for  the  expenditure  of  energy  in  mastica- 
tion due  to  the  presence  of  crude  fiber.  Kellner  found  it 
was  possible  to  estimate  fairly  accurately  the  production 
value  of  concentrated  feeds  by  means  of  these  factors,  but 
in  the  case  of  the  coarse  fodders  carrying  a  much  higher 
proportion  of  fiber  such  a  method  of  computation  was 
not  reliable.  He  found,  however,  that  if  he  deducted 
from  the  figures  obtained  through  the  use  of  the  produc- 
tion values  for  pure  nutrients  617  calories  for  each  pound 
of  crude  fiber  in  the  coarse  fodder  the  computed  value 


182 


THE  FEEDING  OF  ANIMALS 


was  little  different  from  the  real  value.  In  the  use  of 
this  method  only  the  true  proteins  are  brought  into  the 
calculation,  so  that  the  values  are  based  upon  the  digest- 
ible true  proteins  and  the  total  heat  value  of  the  nutrients 
minus  the  energy  expended  on  the  crude  fiber.  The  fol- 
lowing table  illustrates  production  values  that  have  been 
made  up  after  this  method,  with  the  exception  that  the 
deductions  for  crude  fiber  are  less  for  the  green  fodders 
and  roots  than  with  the  dry  coarse  fodders.* 

TABLE  XLIII 


Feeding-stuff 

Total 
dry 
matter 

Digest- 
ible 
protein 

Energy 
value 

Green  fodder  and  silage  — 
Alfalfa    

Pounds 

282 

Pounds 
2.5 

Therms 
per 
100  Ibs. 

12.45 

Corn  silage     . 
Hay  and  dry  coarse  fodders  — 
Clover  hay,  red     

25.6 
847 

1.21 
541 

16.56 
3474 

Corn  stover   

59  5 

1  8 

2653 

Straws  — 
Oat  straw      

908 

1  09 

21  21 

Roots  and  tubers  — 
Rutabagas      .    .  '--.>  .    . 

11  4 

.88 

8. 

Grains  — 
Corn                                                     ; 

89  1 

6  79 

8884 

Oats 

89. 

836 

6627 

By-products  — 
Brewers'  grains,  dried      
Cottonseed  meal  
Gluten  feed,  dry   .    .    /'  .:  

92. 
91.8 
91.9 

19.04 
35.15 
19.95 

60.01 

84.2 
79.32 

Linseed  meal,  new  process  
Wheat  bran 

90.1 

88.1 

29.26 
10.21 

74.67 

48.23 

*  Since  writing  the  above,  Armsby  has  published  a  newly  computed 
and  very  full  table  of  production  values,  based  upon  the  composition  of 
feeding-stuffs  as  found  in  "Feeds  and  Feeding,"  by  Henry  and  Morrison. 
This  table,  computed  by  a  simpler  method  than  the  above,  may  be  found 
in  the  Appendix. 


FUNCTIONS  OF   THE  NUTRIENTS  183 

ENERGY  RELATIONS. — HEAT  REGULATION 

As  has  been  pointed  out,  the  animal  body  is  the  field 
of  numerous  mechanical  activities.  What  is  the  rela- 
tion of  the  several  nutrients  to  these  manifestations  of 
vital  energy  is  an  interesting  and  in  some  ways  an  in- 
tensely practical  matter. 

264.  Relation  of  protein  to  muscular  activity. — The 
belief  prevailed  at  one  time  that  muscular  contraction 
caused  a  wasting  of  the  muscle  substance  which  must  be 
replaced  by  the  protein  compounds  of  the  food;  in  other 
words,  protein  alone  was  believed  to  sustain  the  work  of 
the  animal  body,  both  internal  and  external.    It  would 
follow  from  this  that  the  more  work  is  done  the  more 
protein  is  needed.  This  view  is  no  longer  held.  The  more 
exact  methods  of  modern  research  have  revealed  the 
fact  that  an  increase  of  muscular  effort,  even  up  to  a 
severe  point,  increases  but  little,  if  any,  the  nitrogen 
compounds  of  the  urine,  these  being  the  measure  of  the 
protein  that  is  destroyed. 

265.  Energy  chiefly  from  carbohydrates  and  fats. — 
There  has  come  to  light  a  corresponding  fact  that  the 
consumption  of  fuel  in  the  body  other  than  proteins 
increases    proportionately    with    the    increase    of    work. 
This  means  that  as  animals  are  ordinarily  fed  mechanical 
work  is   largely   sustained   through  the   combustion  of 
carbohydrates    and    fats,    although    a    fairly    generous 
amount  of  protein  seems  to  promote  the  well-being  of 
a  draft  animal. 

266.  Heat   regulation. — As  no   energy  is  ever   lost, 
into  what  is  the  energy  converted  that  is  applied  to 
muscular   contraction?    It  is   concluded   that  muscular 
energy  used  by  the  animal  is  partly  transformed  into 


184  THE  FEEDING  OF  ANIMALS 

external  motion  (work)  and  partly  into  heat,  and  this 
certainly  is  consistent  with  facts  as  observed.  Violent 
exercise  by  the  animal  greatly  increases  the  production 
of  heat.  We  know  this  is  so  because  under  these  con- 
ditions an  increased  amount  of  blood  is  thrown  to  the 
surface  of  the  body,  thereby  greatly  increasing  the  loss 
of  heat  by  radiation;  perspiration  sets  in  and  with  it  the 
consequent  evaporation  of  much  more  moisture,  thus 
disposing  of  much  heat.  The  dog,  and  sometimes  other 
animals,  pants  and  thereby  causes  a  large  loss  of  heat 
from  the  expanded  surface  of  the  moist  tongue.  All  this 
occurs  without  reducing  the  body  temperature  below 
the  normal.  In  fact,  nature  adopts  these  various  devices, 
such  as  increased  circulation  of  the  blood  and  perspira- 
tion, in  order  to  regulate  the  body  temperature  and  pre- 
vent its  rising  above  the  proper  point.  The  explanation 
of  this  greater  heat  during  labor  is  that  the  mechanical 
energy  manifested  by  the  muscles  is  converted  to  heat, 
which  under  circumstances  of  severe  exercise  is  more 
than  enough  to  keep  the  body  at  its  usual  temperature 
and  maintain  the  usual  radiation.  When  it  is  severely 
cold,  on  the  other  hand,  vigorous  exercise  is  sometimes 
necessary  in  order  to  keep  sufficiently  warm. 

267.  Animal  heat  a  secondary  or  waste  product. — 
The  view  now  obtains  that  under  certain  conditions 
body  heat  is  wholly  a  secondary  product,  that  combustion 
first  supports  muscular  activity  with  heat  as  a  by-prod- 
uct; in  fact,  that  at  usual  temperatures  no  food  is 
burned  primarily  to  keep  the  animal  warm.  Under  cer- 
tain conditions  there  may  be  combustion  of  food  for  the 
specific  purpose  of  warming  the  body.  In  any  case, 
animal  heat  is  sustained  either  directly  or  indirectly  by 
the  oxidation  of  the  nutrients. 


FUNCTIONS  OF   THE  NUTRIENTS  185 

268.  The  critical  temperature. — Recent  investigations 
show  that  under  given  conditions  there  is  an  air  tem- 
perature, called  the  "critical  temperature,"  at  which  meta- 
bolism (oxidation)  reaches  a  minimum.  If  the  air  tem- 
perature falls  below  this  point  thus  causing  a  greater 
radiation  of  heat  from  the  body  surface,  increased  oxida- 
tion occurs.  If  the  temperature  of  the  air  rises  above  this 
point  there  is  no  diminution  of  oxidation  but  rather  a 
slight  increase,  hence  the  conclusion  that  there  is  a  mini- 
mum oxidation  necessary  to  the  maintenance  of  the  vital 
functions  which  must  go  on  however  much  the  demands 
for  the  radiation  of  heat  may  be  lessened  by  a  rise  of  the 
air  temperature.  It  is  evident  then  that  at  the  higher 
air  temperatures  there  is  an  excess  of  oxidation  above 
that  which  is  required  for  warming  the  animal,  so  that 
some  heat  must  be  thrown  off  as  a  waste  product.  Which- 
ever way  the  air  temperature  moves  from  the  critical  point 
there  is  heat  regulation,  this  being  chemical  for  the  lower 
temperatures  and  physical  for  the  higher. 

The  critical  temperatures  for  our  various  farm  animals 
have  not  been  determined,  so  that  we  are  not  yet  able  to 
draw  therefrom  conclusions  as  to  the  influence  of  given 
temperatures  upon  production.  The- opinion  is  ventured, 
however,  that  with  animals  protected  by  a  coat  of  hair, 
that  are  kept  under  comfortable  winter  conditions,  the 
temperature  of  the  surrounding  air  does  not  fall  below 
the  critical  point. 

THE  NUTRITIVE  INTER-RELATION  OF  THE  FOOD  COMPOUNDS 
AND  THE  NEED  OF  COMBINING  THESE  IN  THE  RATION 

As  we  have  seen,  the  conclusion  reached  by  many 
extended  and  severe  investigations  is  that  the  compounds 


186  THE  FEEDING  OF  ANIMALS 

of  foods  have  certain  functions  in  common.  For  instance, 
the  proteins,  carbohydrates,  and  fats  are  all  oxidized 
wholly  or  in  part  to  supply  the  necessary  energy  for 
muscular  activity.  The  proteins  then  serve  both  construc- 
tive and  fuel  purposes.  Carbohydrates  and  fats  are 
alike  in  being  sources  of  energy  through  oxidation,  and 
in  being  utilized  for  the  deposition  of  animal  fat.  In 
view  of  these  facts,  the  question  arises  whether  the  physi- 
cal welfare  of  the  animal  requires  the  mixture  of  nutrients 
that  commonly  exist  in  the  average  ration  and  that  is 
enforced  in  the  standards  that  are  recommended  by 
students  of  animal  nutrition.  It  is  certain  that  some 
species  of  animals  may  exist  wholly  on  a  flesh  diet  which 
is  practically  devoid  of  carbohydrates,  but  this  is  not 
true  of  farm  animals. 

269.  Protein   physiologically  necessary. — The   neces- 
sity of  protein  in  the  ration  is  abundantly  demonstrated. 
Many  investigations  have  shown  that  when  the  food 
contains  no  protein,  the  waste  of  body  nitrogen  continues, 
no  matter  how  abundant  is  the  supply  of  carbohydrates 
and  fats.    In  other  words,  a  continuous  protein  cleavage 
is  demanded  by  the  animal   organism,   and   no  other 
nutrients  can  serve  as  a  substitute  for  protein  in  meet- 
ing  this   demand.     If   the   food   contains   no   protein, 
body  tissue  will  be  depleted.    It  cannot  be  said  that 
either  carbohydrates  or  fats  are  an  essential  part  of  the 
diet  in  the  sense  protein  is,  because  it  is  possible  to  sub- 
stitute the  one  for  the  other  as  energy-producers  and  pro- 
tein for  both. 

270.  Carbohydrates    physiologically    economical. — In 
spite  of  these  facts,  it  is  safe  to  assert  that  the  welfare  of 
the  animal  organism  demands  a  food  carrying  a  mixture 
of  the  three  classes  of  nutrients.    The  larger  part  of  the 


FUNCTIONS  OF   THE  NUTRIENTS  187 

animal's  food  is  used  for  the  production  of  energy,  and  it 
is  physiologically  economical  that  this  energy  be  largely 
supplied  by  the  non-nitrogenous  nutrients,  particularly 
carbohydrates.  If  the  proteins  are  broken  down  to 
supply  energy,  there  is  always  a  definite  proportion  of 
urea  and  uric  acid  residue  that  must  be  eliminated  through 
the  kidneys.  An  unnecessarily  heavy  protein  diet  bur- 
dens these  organs  and  floods  the  system  with  these  nitrog- 
enous wastes.  On  the  other  hand,  the  carbohydrates, 
when  not  stored  as  fat,  are  completely  oxidized  to  the 
simplest  compounds,  carbon  dioxid  and  water,  which  are 
eliminated  through  the  lungs  and  skin,  part  of  the  water 
so  formed  acting  as  a  solvent  of  the  urinary  compounds. 
Investigation  seems  to  prove  conclusively  that  the 
animal  body  has  a  physiological  preference  for  carbo- 
hydrates over  the  fats  or  other  nutrients  as  a  source  of 
energy.  After  the  free  ingestion  of  sugar,  the  respiratory 
quotient  in  certain  experiments  has  become  1.00  when 
just  previously  it  was  much  less  than  1.00.  This  demon- 
strates that  while  fat  was  being  oxidized  before  the  sugar 
was  taken,  the  oxidation  immediately  changed  wholly  to 
the  sugar.  This  indicates  the  physiological  adaptability 
of  starches  and  sugars  for  maintaining  muscular  activity. 
271.  Protein-sparers. — The  carbohydrates  and  fats 
are  sometimes  classed  as  "protein-sparers."  This  means 
that,  with  an  adequate  supply  of  these  bodies  in  the  food, 
protein  destruction  may  be  reduced  to  the  lowest  pos- 
sible limit.  To  illustrate,  if  a  man  doing  moderate  work 
were  maintaining  an  energy  balance  when  eating  of 
digestible  nutrients  218  grams  of  protein,  400  grams  of 
carbohydrates,  and  56  grams  of  fat,  and  100  grams  of 
digestible  carbohydrates  were  added  to  the  daily  food, 
approximately  100  grams  of  digestible  protein  could 


188  THE  FEEDING  OF  ANIMALS 

undoubtedly  be  withdrawn  from  the  daily  food  without 
causing  any  drain  upon  body  protein  to  meet  the  demands 
of  the  organism.  As  stated,  however,  such  a  substitution 
cannot  be  carried  beyond  certain  limits  without  depress- 
ing the  protein-supply  below  the  body  needs  for  main- 
tenance. Fats  are  not  as  efficient  protein-sparers  as  are 
carbohydrates.  To  be  more  explicit,  fats  and  carbo- 
hydrates do  not  replace  protein  in  proportion  to  their 
energy  equivalents,  carbohydrates  being  the  more  effi- 
cient. In  brief,  then,  experience  and  science  both  indicate 
that  carbohydrates  are  the  most  healthful,  and  physiologi- 
cally the  most  economical,  source  of  a  large  proportion 
of  the  food  energy.  There  is  every  justification  for  the 
relative  abundance  of  starch  foods  in  the  rations  of 
farm  animals. 

272.  Nutritive  value  of  the  gums. — The  question  has 
been  raised  as  to  whether  the  gums  (pentosans)  which 
exist  so  abundantly  in  many  coarse  foods  and  in  some 
grain  products  like  wheat  bran  are  not  inferior  as  sources 
of  energy  to  the  other  more  soluble  carbohydrates.  It 
has  been  observed  that  the  sugars  which  result  from  the 
action  of  ferments  on  these  bodies  have,  in  some  in- 
stances, not  been  oxidized,  but  have  passed  off  in  the 
urine  as  such.  It  appears  that  under  normal  and  usual 
conditions  this  does  not  occur  to  any  extent  with  herbiv- 
ora.  Pentosans  are  present  in  all  rations  for  farm 
animals,  and  we  have  no  reason  for  believing  that  the 
pentose  sugars  are  constant  ingredients  of  their  urine. 
Muccollum  and  Brannon  studied  extensively  the  fate 
of  various  pentosans  in  the  digestive  tract  of  bovines. 
They  found  that  these  compounds  are  not  equally  diges- 
tible from  all  sources.  Those  from  the  corn,  oat,  and  wheat 
plants  were  studied  and  the  range  of  digestibility  was  46 


FUNCTIONS   OF   THE  NUTRIENTS  189 

to  67  per  cent.  The  corn-plant  pentosans  were  digested 
most  fully  and  those  from  the  wheat  plant  least  so. 

Swartz  concluded  from  extensive  investigation  that 
the  water-soluble  hemicelluloses  are  resistant  to  the 
action  of  enzyms  and  disappear  from  the  digestive  tract 
only  in  proportion  as  they  are  attacked  by  bacteria. 
Pentosans  and  mannans  which  are  hydrolized  by  bacterial 
action  were  found  to  be  almost  wholly  digested,  while 
galactans  were  largely  excreted  as  such.  In  considering 
their  digestibility  the  groups  of  hemicelluloses  evidently 
must  be  considered  separately.  In  any  case,  digestibility 
should  not  be  considered  as  a  measure  of  nutritive 
value. 

273.  Relative  importance  of  the  nitrogen  compounds 
of  feeding-stuffs. — What  is  known  as  the  crude  protein 
of  feeding-stuffs  is  the  total  nitrogen  multiplied  by  the 
factor  6.25.  As  has  been  stated,  protein  as  so  estimated 
contains  a  variety  of  nitrogen  compounds  that  are  unlike 
in  character  and  exist  in  various  cattle  foods  in  greatly 
unlike  proportions.  For  example,  a  much  larger  part  of 
the  crude  protein  of  coarse  fodders  and  roots  consists  of 
amides  than  is  the  case  with  grains,  the  latter  being  cor- 
respondingly richer  in  true  proteins.  If,  therefore,  it  is 
found  that  the  true  proteins  differ  from  the  amides  in 
function  and  value,  we  have  established  one  point  of 
unlikeness  between  grain  foods  and  roots  or  the  coarse 
fodders.  We  have  convincing  proof  that  the  true  pro- 
teins are  the  main  flesh-formers  found  in  cattle  foods. 
Are  the  amides  such  as  glutamin  and  asparagin  also  flesh- 
formers?  Earlier  experiments  with  these  compounds  led 
to  the  conclusion  that  they  may  exercise  a  protective 
function  toward  the  true  proteins  and  thus  reduce  the 
minimum  of  such  proteins  necessary  to  satisfy  the  needs 


190  THE  FEEDING  OF  ANIMALS 

of  an  animal  under  given  conditions  of  production.  Some 
of  the  more  recent  investigations  indicate  that  the  amides 
should  be  classed  as  to  function  with  the  true  proteins,  or, 
in  other  words,  that  they  may  take  part  in  the  synthesis 
of  the  proteins  that  are  used  constructively  in  the  animal 
body  though  probably  with  not  the  same  percentage  of 
efficiency.  Evidence  exists,  moreover,  that  the  different 
amides  are  not  of  equal  value.  (See  Par.  85.) 

274.  Relative  nutritive  efficiency  of  the  true  pro- 
teins.— Notwithstanding  possible  function  of  the  amide 
compounds  in  the  synthesis  of  animal  proteins,  the  true 
proteins  of  our  cattle  foods  must  be  regarded  as  the  main 
flesh-formers.  There  are,  however,  many  true  proteins 
which  are  unlike  in  their  constitution.  It  is  desirable 
to  know  whether  these  single  proteins  differ  in  nutritive 
value  for  specific  purposes,  like  growth  or  milk  forma- 
tion. Are  the  alcohol-soluble  proteins,  such  as  gliadin 
and  zein  of  equal  value  with  an  albumin,  a  globulin,  or 
casein?  Reference  has  been  made  to  the  fact  that  while 
the  cleavage  products  of  these  various  proteins  (amino 
acids),  or  what  are  called  the  building-stones,  are  to  a 
great  extent  similar  as  to  kind,  these  building-stones  are 
not  found  in  the  same  proportions  in  the  several  proteins, 
and  with  some  proteins  certain  building-stones  are  lack- 
ing. The  investigations  of  Mendell  and  Osborne,  pre- 
viously mentioned,  indicate  great  unlikeness  in  nutritive 
function  and  value.  It  is  found,  for  instance,  that  the 
gliadin  of  wheat  and  rye  does  not  function  as  does  the 
casein  in  milk  and  that  zein  is  particularly  inefficient  as  a 
means  of  even  sustaining  life,  and  it  is  significant  that 
the  gliadin  is  deficient  in  lysine,  and  that  zein  is  further 
lacking  in  tryptophane,  whereas  the  proteins  of  the  animal 
body  contain  both  of  these  animo  acids.  (See  Par.  85.) 


FUNCTIONS  OF   THE  NUTRIENTS  191 

275.  A  single  amino  acid  a  limiting  factor. — Evidence 
on  this  question  is  seen  in  experimental  work  carried  on 
by  Osborne  and  Mendell.  These  authors  brought  rats  to 
full  size  and  kept  them  in  health  when  the  diet  contained 
18  per  cent  of  casein.  When  the  casein  was  reduced  to  12 
per  cent,  growth  fell  below  the  normal.  When  reduced  to 
9  per  cent,  growth  was  promptly  limited  by  the  protein 
factor.  If,  however,  cystine  was  added  to  the  9  per  cent 
of  casein,  the  ration  was  rendered  much  more  efficient 
for  growth,  showing  that  the  presence  of  an  insufficient 
quantity  of  this  one  building-stone  was  the  limiting 
factor.  Similar  results  were  secured  in  experiments  with 
edestin.  When  15  per  cent  of  the  ration  consisted  of 
edestin,  normal  growth  was  secured,  but  not  with  9  per 
cent.  The  addition  of  lysine  to  the  9  per  cent  of  edestin 
caused  an  improvement.  Lact-albumin  was  efficient 
because  all  the  building-stones,  including  lysine  and  trypto- 
phane,  are  relatively  abundant  in  this  protein. 

McCollum  has  determined,  through  a  series  of  experi- 
ments in  which  he  fed  single  foods  to  pigs,  the  proportion 
of  protein  used  by  the  animal  for  building  protein  tissue. 
His  conclusions  are  as  follows: 

ljer  cent 
deposited 

Oil  meal  proteins 16-17 

Wheat  proteins 20 

Corn  proteins 24 

Oat  proteins     . 25 

Wheat  germ 40 

Casein 45 

Skimmed  milk  proteins .  63 

The  author  also  gives  figures  showing  that  the  proteins 
of  one  food  supplement  those  of  another  in  producing 
more  growth  when  the  two  foods  are  combined  than  when 
fed  singly: 


192  THE  FEEDING  OF  ANIMALS 

Per  cent 
deposited 

Corn  proteins  90  per  cent,  oil  meal  proteins  10  per  cent  .  31 
Corn  proteins  75  per  cent,  oil  meal  proteins  25  per  cent  .  37 
Corn  proteins  60  per  cent,  oil  meal  proteins  40  per  cent  .  32 

Those  proteins  are  most  efficient,  evidently,  whose 
building-stones  correspond  most  nearly  in  proportion  to 
those  of  animal  proteins. 

276.  Nutritive  value  of  the  gelatinoids. — The  gelati- 
noids  which  belong  to  the  class  of  non-proteins  cannot 
be  regarded  as  taking  the  place  of  proteins.    It  has  been 
found  that  they  protect  protein  from  cleavage  and  thus 
make  a  minimum  protein-supply  more  efficient  but  they 
do  not  function  in  the  synthetical  processes  as  the  true 
proteins  do.    Gelatin  also  is  lacking  in  certain  building- 
stones,  namely  tyrosine,  cystine,  and  tryptophane.    This 
consideration  of  the  protein  compounds  on  the  basis  of 
their  building-stones  is  a  new  and  interesting  point  of 
view  and  leads  to  the  conclusion  that  those  proteins  are 
most  efficient  for  constructive  purposes  whose  building- 
stones  correspond  in  kind  and  proportion  most  nearly  to 
those  of  the  proteins  in  the  animal  body. 

277.  Synthesis  in  the  animal  of  phosphorus-bearing 
proteins. — One  interesting  question  which  has  been  con- 
sidered   is  whether   the   nucleo-proteins   and    phospho- 
proteins  which  are  found  so  abundantly  in  eggs  and  in 
milk  must  be  supplied  as  such  in  the  food,  or  whether 
they  may  be  built  up  in  the  animal  from  the  simple  pro- 
teins and  phosphates.    If  we  could  learn  that  the  food 
must  contain  these  peculiar  proteins  all  ready  for  use, 
then  we  would  have  a  valuable  suggestion  for  feeding 
cows  and  poultry.   It  now  seems  that  this  is  not  the  case. 
The  sea  salmon,  which,  during  its  stay  up  the  river,  is 
believed  to  take  no  food,  undoubtedly  produces  large 


FUNCTIONS  OF   THE  NUTRIENTS  193 

masses  of  eggs  from  the  body  substance,  and  it  seems 
unlikely  that  so  much  nuclein  as  is  needed  exists  in  the 
flesh.  If  a  cow  gives  thirty  pounds  of  milk  daily,  nearly 
or  quite  a  pound  of  casein  must  come  from  somewhere, 
and  there  is  no  evidence  that  any  ordinary  ration  would 
contain  so  large  a  quantity  of  phospho-proteins  of  like 
constitution.  Hens'  eggs  are  rich  in  nuclein,  beyond  any 
amount  which  the  food  seems  likely  to  supply.  Experi- 
mental evidence  supports  these  general  inferences. 

278.  The  function  of  certain  unidentified  bodies. — 
An  important  addition  to  the  science  of  nutrition  is  the 
recent  demonstration  that  certain  compounds  are  asso- 
ciated with  animal  foods  which  have  a  growth-promoting 
function  and  in  the  absence  of  which  either  artificial  or 
natural  foods  fail  to  sustain  growth  and  even  life.  (See 
Par.  118.)  It  has  been  known  for  some  time  that  some 
such  substance  was  associated  with  the  shells  of  rice  which, 
when  given  to  animals  afflicted  with  beri-beri  from  eating 
polished  rice,  would  restore  them  to  a  normal  condition. 
Substances  of  this  class  were  named  vitamines  by  Funk. 

An  enlargement  of  the  knowledge  of  bodies  of  this 
class  was  led  up  to  through  studies  by  American 
investigators  as  to  the  relative  nutritive  value  of  single 
proteins.  Heretofore  the  attention  of  investigators  in 
animal  nutrition  has  been  focussed  chiefly  upon  the  con- 
structive and  energy  functions  of  the  various  classes  of 
nutrients,  and  it  was  expected  that  when  the  proteins, 
carbohydrates,  and  ash  compounds,  supposedly  necessary 
to  complete  nutrition,  were  all  supplied  to  an  animal, 
satisfactory  results  would  be  accomplished.  It  was  dis- 
covered that,  when  there  was  fed  a  combination  of  puri- 
fied nutrients  artificially  prepared  with  great  care  and  in 
accordance  with  the  best  knowledge  of  the  needs  of  the 


194  THE  FEEDING  OF  ANIMALS 

animal,  growth  was  not  secured.  When,  however,  what 
was  termed  "protein  free"  milk  was  used  in  connection 
with  such  a  preparation,  normal  growth  resulted.  This 
result,  observed  by  Mendel  and  Osborn,  led  up  to  a 
series  of  investigations  in  which  Hart  and  McCollum  have 
taken  a  prominent  part.  It  now  appears  from  abundant 
data  that  two  classes  of  growth-promoting  substances 
exist,  which  have  been  termed  Fat-soluble  A  and  Water- 
soluble  B,  terms  which  are  temporary  until  these  bodies 
have  been  identified.  The  proof  of  the  existence  of  these 
bodies  has  been  illustrated  as  follows  (McCollum):  If  to 
a  mixture  of  purified  proteins,  carbohydrates,  and  salt 
mixtures  containing  all  the  salts  found  in  the  animal 
body  there  is  added  either  a  small  amount  of  egg  yolk 
or  milk  powder,  growth  proceeds  normally;  whereas  the 
mixture  of  nutrients  before  such  addition  fails  to  produce 
growth.  If  the  dried  egg  yolk  is  extracted  with  ether  to 
remove  the  fat,  the  addition  of  the  residue  does  not  give  the 
desired  result.  The  addition  of  the  fat  alone  also  is  shown 
to  be  futile.  If,  however,  there  is  added  to  the  nutritive 
mixture  along  with  the  extracted  egg-fat  a  water-extract 
of  the  fat-free  yolk  residue,  growth  is  normal.  Similar 
results  occur  with  other  substances,  such  as  milk  powder. 
This  is  the  basis  for  the  classification  into  Fat-soluble  A 
and  Water-soluble  B,  both  of  which  are  essential  to 
growth.  It  appears  that  the  milk  of  an  animal  which  has 
been  fed  on  purified  nutrients  fails  to  sustain  her  young, 
showing  that  these  growth-promoting  substances  are 
transferred  from  the  food  to  the  mother's  milk  and  are  not 
synthesized  within  the  body. 

It  seems  certain  that  the  disease  known  as  beri-beri, 
brought  about  by  a  restricted  diet  of  polished  rice,  is  due 
to  the  absence  of  one  of  these  classes,  and  it  is  probable 


FUNCTIONS  OF   THE  NUTRIENTS  195 

that  pelagra,  prevalent  in  the  South  where  the  diet  of 
many  individuals  is  considerably  restricted,  is  due  to  the 
absence  or  insufficient  supply  of  one  or  both  of  these 
classes. 

These  accessory  substances  appear  to  be  abundant  in 
egg,  milk,  and  the  forage  portion  of  many  plants,  Fat- 
soluble  A  being  deficient  in  the  body  fats  of  animals  and 
absent  from  the  fats  or  oils  of  many  species  of  plants. 
The  knowledge  of  the  presence  or  absence  of  these  growth- 
promoting  substances  in  cattle  foods  will  undoubtedly  be 
enlarged  as  investigation  proceeds. 

It  is  shown  in  experiments  by  Hart  and  McCollum 
that  when  the  rations  of  animals  were  restricted  to  a  single 
plant,  that  the  wheat  germ  contains  a  toxic  body.  Ani- 
mals fed  wholly  on  the  corn  plant  or  its  products  developed 
normally  and  produced  young.  Those  fed  on  the  wheat 
plant  or  its  products,  without  the  addition  of  other  food, 
failed  to  make  satisfactory  growth  and  to  produce  vigor- 
ous young.  Similar  results  were  obtained  with  wheat 
products  when  fed  to  swine.  Such  results  with  the  wheat 
plant  were  evidently  not  due  to  a  lack  of  nutrients  but 
investigation  showed  that  the  operating  cause  was  a 
poisonous  principle  located  in  the  fat  of  the  wheat,  this 
principle  being  removed  when  the  wheat  oil  was  extracted. 
We  have  here,  then,  an  example  of  a  toxic  body  con- 
tained in  one  of  the  most  common  of  our  feeding-stuffs, 
the  effect  of  which  has  been  less  observed  because  wheat 
by-products  have  constituted  only  a  portion  of  the  food 
of  the  animal. 

279.  Relation  of  production  values  to  profit  from 
feeding  animals. — The  production  from  a  given  quantity 
of  food  varies  greatly  under  unlike  conditions.  It  can 
scarcely  be  doubted  that  the  proportion  of  the  available 


196  THE  FEEDING  OF  ANIMALS 

nutrients  which  are  consumed,  that  is,  burned  as  fuel, 
increases  as  the  ration  increases  above  what  is  needed 
for  maintenance,  and  inversely  the  proportion  of  the 
nutrients  stored  in  the  body  as  flesh  and  fat  undoubtedly 
is  less  the  greater  the  quantity  fed  is  in  excess  of  the 
demands  for  maintenance.  A  large  excess  over  mainte- 
nance is  relatively  less  efficient  than  a  small  one  in  the 
production  of  flesh  or  milk.  There  comes  a  point  where 
additional  food  produces  no  additional  gain,  but  only 
additional  consumption.  The  age  of  the  growing  animal 
and  the  condition  of  a  fattening  animal  also  modify  the 
efficiency  of  the  food  for  production  purposes,  as  does 
individuality,  and  with  a  cow  the  stage  in  the  period  of 
lactation.  With  all  these  variations  no  averages  are  pos- 
sible which  express  with  any  definiteness  fixed  production 
values  for  the  different  nutrients. 


CHAPTER  XI 
LAWS  OF  NUTRITION 

THE  preceding  pages  have  been  devoted  to  a 
discussion  of  the  origin  of  cattle  foods,  what  they  are 
in  substance,  how  their  nutrients  are  made  available  and 
how  used.  So  far  no  attempt  has  been  made  to  bring 
together  in  a  concise  form  what  may  be  called  the  funda- 
mental principles  or  laws  of  nutrition.  It  is  desirable,  how- 
ever, before  passing  to  the  consideration  of  the  practice 
of  cattle-feeding,  to  summarize  the  principles  on  which 
the  science  of  cattle-feeding  is  based. 

280.  All  energy  and  building-material  applied  to  the 
maintenance  and  growth  of  the  animal  body  come  from 
the  food,  water,  and  oxygen  being  included  in  this  term. 
The  animal  originates  neither  energy  nor  matter. 

281.  Only  that  portion  of  the  food  which  is  digested, 
i.  e.,  that  which  is  rendered  soluble  and  diffusible  by  the 
digestive  fluids  so  that  it  passes  into  the  blood,  is  avail- 
able for  any  use  whatever. 

282.  The  unutilized  food  and  the  wastes  pass  from  the 
body  in  several  directions.   The  undigested  part  mainly 
constitutes  the  solid  excrement  or  feces.    The  urea  and 
other  nitrogenous  compounds  which  are  the  unoxidized 
portion  of  the  protein,  pass  out  wholly  in  the  urine.   All 
digested  nitrogen  not  stored  is  found  here.    The  carbon 
dioxid  is  eliminated  through  the  skin  and  lungs,  chiefly 
the  latter,  and  water  is  disposed  of  through  the  kidneys, 
skin,  and  lungs. 

(197) 


198  THE   FEEDING  OF   ANIMALS 

283.  The  digested  food  is  used  in  two  general  directions, 
(a)  for  the  production  of  energy  and  (6)  for  constructive 
purposes. 

(a)  The  food  energy  is  made  available  through  com- 
bustion, i.  e.,  the  oxidation  of  the  carbon  compounds  of 
the  food  to  simpler  substances,  carbon  dioxid  and  water, 
thus  liberating  the  energy  stored  in  the  plant  during  its 
growth.  Protein  is  never  fully  oxidized,  but  carbohydrates 
and  fats  may  be.    All  the  organic  nutrients  may  be  oxi- 
dized to  produce  energy,  the  phycological  energy  values 
of  protein,  carbohydrates,  and  fats  being  approximately 
as  1,  1,  2.25.    The  larger  part  of  the  energy  used  by  farm 
animals  comes  from  the  carbohydrate  portion  of  the  food. 
This   liberated   energy  finds   expression   in   the  animal 
organism  in  various  ways,  as  heat,  mechanical  energy  or 
motion,  and  chemical  transformations.   The  total  energy 
of  food  is  never  all  available  to  the  animal  because  of  a 
loss  in  the  excreta  and  gases.   Moreover,  the  productive 
energy  is  much  less  than  the  available  energy,  because 
much  energy  is  used  in  the  work  of  appropriation  of  the 
food. 

(b)  The  food  compounds  are  used  for  constructive 
purposes,  either  without  changing  their  general  charac- 
ter, as,  for  instance,  the  building  of  muscular  tissue  from 
the  plant  proteins,  or  they  may  be  reorganized  into  bodies 
of   a  very  different    character,  as  in  the  formation  of 
animal  fats  from  starch  and  sugar.    Protein  is  used  to 
construct  muscular  tissue,  in  fact,  all  the  nitrogenous 
parts,  and  is  a  source  of  fat.    Carbohydrates  can  only  be 
used  constructively  for  the  formation  of  fat,  and  the  same 
is  true  of  food  fats  or  oils.   Mineral  matter  is  needed  for 
the  formation  of  bone,  enters  into  the  constitution  of  the 
soft  parts,  and  has  important  metabolic  functions. 


LAWS  OF  NUTRITION  199 

284.  The  matter  of  the  digested  food,  including  water 
and  oxygen,  is  exactly  equal  to  that  stored  in  the  body  or 
in   milk,  or  both,  plus  that   in  waste  products — feces, 
water,  carbonic  acid,  and  urine  solids.    Such  a  balance 
may  not  be  maintained  for  any  particular  day,  but  will 
ultimately  be  found  to  exist. 

285.  Under  given  conditions  of  species,  sex,  climate, 
and  use,  a  definite  amount  of  digested  organic  matter  is 
necessary  to  maintain  a  particular  animal  without  gain 
or  loss  of  body  substance.    This  means  simply  that  tis- 
sue wastes  must  be  replaced,  and  the  fuel-supply  must 
be  kept  up. 

If  the  animal  receives  no  food,  or  less  than  the  amount 
needed  for  maintenance  purposes,  tissue  waste  and  the 
production  of  energy  do  not  cease,  but  go  on  wholly  or 
in  part  at  the  expense  of  the  body  substance. 

286.  Food  supplied  above  a  needed  maintenance  quan- 
tity may  be  utilized  for  the  production  of  new  substances 
or  work  or  may  be  eliminated   in  .part  increasing  the 
waste.    Within  limits,  both  things  generally  occur.    In 
the  proper  sense  of  the  term,  no  production  ever  occurs 
without  an  excess  of  food  above  maintenance  require- 
ments.   Milk  formation  may  sometimes  go  on  at  the 
expense  of  the  body  substance,  but  with  proper  feeding, 
milk,  flesh  or  muscular  work  are  produced  at  the  expense 
of  food  supplied  in  excess  of  that  needed  for  maintenance. 

287.  Regard  must  be  had  to  the  supply  of  particular 
nutrients  as  well  as  of  total  food.    Even  with  an  animal 
doing  no  work  and  giving  no  milk  a  certain  amount  of 
protein  will  be  broken  up  constantly  into  urea  and  simi- 
lar compounds,  an  amount  which  will  be  withdrawn  from 
the  body  tissues  to  the  extent  that  it  is  not  supplied  by 
the  food.    In  addition  to  this,  a  milch  cow,  for  instance, 


200  THE  FEEDING   OF  ANIMALS 

must  have  protein  for  the  formation  of  the  nitrogen  com- 
pounds of  the  milk,  or  a  steer  for  the  growth  of  flesh,  in  a 
quantity  proportional  to  the  production,  and  food  must 
supply  it.  There  is,  therefore,  a  minimum  supply  of  pro- 
tein, which,  in  a  particular  case,  is  necessary  for  the 
maintenance  and  for  constructive  purposes,  less  than 
which  ultimately  diminishes  production  to  the  extent  of 
the  deficiency,  or  else  requires  the  use  of  body  tissue. 

288.  The  different  classes  of  nutrients  are  to  some 
extent  interchangeable  in  their  functions.  That  is  to  say, 
all  the  organic  nutrients  may  be  burned  to  supply  energy. 
Protein  may  be  so  used  even  to  withdrawing  it  from  the 
purposes  to  which  it  is  necessary  unless  the  carbohydrates 
or  fats  are  sufficient  to  protect  it  from  being  consumed  as 
fuel.  A  proper  supply  of  the  non-nitrogenous  nutrients 
is  required,  therefore,  to  insure  the  application  of  the 
necessary  minimum  of  food  protein  to  its  peculiar  uses. 
The  carbohydrates  and  fats  are  the  physiologically  eco- 
nomical source  of  the  main  part  of  the  energy  used  by 
farm  animals. 


CHAPTER  XII 
SOURCES  OF  KNOWLEDGE 

THE  foregoing  chapters  embody  many  statements  of 
principles  and  facts  which  have  been  made  positively 
and  without  modification.  To  quite  an  extent  these 
are  based  upon  the  conclusions  of  scientific  men,  i.e., 
conclusions  which  have  been  reached  after  such  study 
of  the  problems  involved  as  is  competent  to  secure  ac- 
curate information.  In  some  cases  this  study  has  been 
severe  and  long  continued,  having  been  carried  on  by 
the  use  of  methods  and  apparatus  capable  of  the  most 
precise  measurements.  Moreover,  in  the  investigations 
of  science  an  effort  has  been  made  to  proceed  logically, 
so  that  the  results  attained  shall  not  be  fallacious.  Not- 
withstanding the  fact  that  a  great  deal  of  our  knowledge 
is  the  result  of  an  earnest  and  impartial  search  after 
truth,  under  conditions  especially  favorable  to  its^is- 
covery,  many  persons  are  disposed  to  give  more  credit  to 
traditions  and  conclusions  of  practice  than  to  the  care- 
fully prepared  verdicts  of  science.  It  may  not  be  out  of 
place,  therefore,  to  present  in  this  connection  some  of  the 
considerations  and  methods  which  have  to  do  with  the 
acquisition  of  knowledge  concerning  animal  nutrition, 
for  this  may  aid  us  to  appreciate  the  value  of  well-estab- 
lished facts  and  to  exercise  caution  in  accepting  the 
verdicts  either  of  science  or  of  practice  before  they  are 
thoroughly  justified. 

There  are  three  general  ways  in  which  we  may  be 
(201) 


202  THE  FEEDING  OF  ANIMALS 

said  to  have  acquired  knowledge  in  regard  to  feeding 
animals : 

1.  The  observation  of  ordinary  .practice. 

2.  Practical  experiments,  so  called. 

3.  Scientific  investigation. 

289.  Conclusions  from  feeding  practice. — Until  within 
recent  years,  the  practice  of  cattle-feeding  has  been 
entirely  governed  by  the  conclusions  drawn  from  ordi- 
nary practice.  Among  the  many  men  engaged  in  animal 
husbandry,  certain  ones  possessed  of  more  than  average 
powers  of  observation  and  business  ability  have  secured 
good  results  with  certain  feeding-stuffs  and  methods  of 
feeding,  and  their  practice  has  been  accepted  by  their 
neighbors  with  no  further  demonstration  than  that  these 
successful  farmers  sold  fat  cattle  and  obtained  large 
returns  from  the  dairy.  During  the  centuries  that  man 
has  had  domestic  animals  under  his  care,  certain  results 
have  appeared  to  follow  from  certain  systems  of  feeding 
or  the  use  of  certain  foods,  and  upon  these  so-called 
practical  observations  the  feeder  has  built  his  creed. 

In  these  ways  there  have  come  to  be  accepted,  some- 
times locally  and  sometimes  generally,  standards  of 
feeding  as  to  quantity,  kind  of  ration,  and  times  of  feed- 
ing. At  the  same  time,  it  was  necessary  only  to  attend 
a  farmers'  convention  fifty  years  ago  to  become  con- 
vinced of  a  great  variety  of  opinions  as  to  the  best 
methods  of  practice.  In  fact,  opinion  was  the  court  of 
last  resort.  There  were  then  no  known,  well-estab- 
lished fundamentals  to  which  appeal  could  be  made  as 
a  basis  for  discussion.  While  many  false  notions  were 
entertained,  many  of  the  beliefs  then  prevailing  were 
undoubtedly  correct  or  contained  a  germ  of  truth.  It 
is  generally  safe  to  assume  that  when  an  opinion  is 


SOURCES  OF  KNOWLEDGE  203 

widely  and  persistently  held  it  is  not  altogether  with- 
out reason  or  foundation.  It  is  often  the  expression,  in 
more  or  less  correct  terms,  of  some  important  principle. 
No  one  should  lightly  turn  aside  from  widespread  tra- 
ditions and  convictions  in  regard  to  any  line  of  practice. 
A  knowledge  of  the  precepts  governing  the  feeder's  art 
that  are  the  accumulation  of  experience  in  the  care  of 
animals  is  to  be  respected  and  is,  to  a  great  extent,  essen- 
tial to  successful  practice.  It  is  also  true  that  little  sub- 
stantial progress  can  be  realized  in  any  art  if  its  under- 
lying truths  are  not  understood,  for  when  this  is  the  case 
the  results  of  experience  under  one  set  of  conditions  do 
not  serve  as  a  guide  under  circumstances  entirely  different. 

290.  Practical  feeding  experiments. — With  the  advent 
of  modern  science  and  of  the  efforts  to  utilize  it  in  agri- 
culture, an  attempt  has  been  made  to  search  for  impor- 
tant truths  more  systematically,  an  effort  undertaken 
chiefly  by  experiment  stations.    As  one  means  of  gain- 
ing knowledge,  these  institutions,  and  to  some  extent 
private  farmers,  have  conducted  many  so-called  practical 
feeding  experiments  in  order  to  verify  present  beliefs, 
test  theories,  and  solve  existing  problems.  The  relative 
value  of  various  feeding-stuffs  and  rations  for  producing 
growth  and  milk  and  the  influence  of  different  fodders 
and  grain  foods  upon  the  quality  of  the  product  have 
been   the   subjects   of   numerous   feeding   tests.     Much 
valuable  information  has  been  secured  in  this  way,  but 
there  has  not  always  been  a  full  recognition,  even  by 
experiment  stations,  of  the  limitations  which  should  be 
observed  in  drawing  conclusions  from  this  manner  of 
experimentation. 

291.  Inconclusiveness  of    ordinary    feeding    experi- 
ments.— In  order  to  view  this  matter  more  in  detail,  let  us 


204  THE  FEEDING  OF   ANIMALS 

consider  experiments  in  testing  rations  for  growth  and 
milk  production.  The  usual  method  of  procedure  with 
such  feeding  trials  is  either  to  feed  two  lots  of  animals 
on  the  rations  to  be  compared  and  note  the  compara- 
tive growth  or  milk  yield,  or  to  feed  the  same  lot 
on  one  ration  for  a  time  and  then  change  to  another 
ration. 

If  these  tests  are  made  with  growing  or  fattening 
animals,  the  increase  in  live  weight  is  taken  as  the  meas- 
ure of  the  relative  efficiency  of  the  rations  compared. 
It  should  be  said  of  these  experiments  that  then*  appar- 
ent verdict  is  to  be  accepted  with  great  caution,  and 
definite  conclusions  are  not  justified  until  repeated 
extended  trials  of  two  rations  or  of  two  systems  of  feed- 
ing, made  with  the  use  of  all  possible  precautions  against 
error,  and  under  a  variety  of  conditions,  give  uniform 
and  consistent  results  in  the  same  direction.  There  are 
several  reasons  why  this  is  so,  the  main  one  being  that 
the  increase  in  the  weight  of  an  animal  is  an  uncer- 
tain measure  of  actual  growth.  Variations  in  the  con- 
tents of  the  alimentary  canal  due  to  the  irregularity  of 
fecal  discharge  and  to  a  lack  of  uniformity  in  the  water 
drank  may  cause  temporary  variations  in  the  live  weight 
of  considerable  magnitude.  Moreover,  the  nature  of  the 
growth  of  body  substance  is  revealed  neither  by  the  mere 
weighing  of  an  animal  nor  by  his  general  appearance. 
Even  if  the  changes  in  weight  are  due  to  an  increase  of 
body  tissue,  this  may  be  more  largely  water  in  one  case 
than  in  another,  so  that  the  real  contribution  of  the  food 
to  the  dry  substance  of  the  body  may  not  be  shown. 
Nor  is  the  character  of  the  solids  deposited  in  the  animal 
discovered  by  merely  weighing  him.  In  fact,  by  such 
practical  experiments  we  simply  learn  that  one  set  of 


SOURCES  OF   KNOWLEDGE  205 

animals  has  gained  more  or  less  pounds  of  weight  than 
another  set,  but  the  why  and  the  how  are  not  explained. 

Practically  the  same  considerations  pertain  to  feed- 
ing tests  for  milk  production.  When  the  milk  flow  from 
one  ration  is  larger  than  from  another,  we  can  easily 
satisfy  ourselves  as  to  the  comparative  yield  of  milk 
solids,  which  is  the  real  test  of  such  production;  but  we 
are  not  able  to  decide  whether  the  cow  either  may  not 
have  contributed  to  the  milk  secretion  from  the  substance 
of  her  own  body,  or  may  not  have  gained  in  body  sub- 
stance, the  extent  of  such  loss  or  gain  being  greater, 
perhaps,  with  one  ration  than  with  another. 

Even  if  these  uncertainties  did  not  exist,  we  have 
the  still  greater  disadvantage  of  not  learning  by  this 
means  why  a  particular  combination  of  feeds  has  superior 
qualities  for  causing  growth  or  sustaining  milk  secretion. 
The  mere  data  showing  that  an  animal  ate  so  many 
pounds  of  food  and  produced  so  many  pounds  of  beef  or 
milk  are  important  business  facts,  but  they  reveal  noth- 
ing concerning  the  uses  of  the  several  classes  of  nutrients 
and  of  themselves  furnish  slight  basis  for  developing  a 
rational  system  of  feeding.  We  must  somehow  learn  the 
function  of  protein,  carbohydrates,  and  fats  in  main- 
taining the  various  classes  of  animals  and  the  real  effect  of 
varying  the  source,  quantity,  and  relative  proportions  of 
these  nutrients  before  we  can  draw  safe  general  conclusions. 

292.  Chemical  and  physiological  studies. — As  pre- 
liminary to  more  comprehensive  and  convincing  methods 
of  investigating  feeding  problems,  there  has  been  going 
on  during  many  years  a  necessary  study  of  the  compounds 
which  are  found  in  plants  and  animals.  Much  has  been 
learned  about  the  ultimate  composition  and  the  consti- 
tution of  the  proteins,  carbohydrates,  and  fats,  their 


206  THE  FEEDING  OF  ANIMALS 

physical  and  chemical  properties,  the  compounds  into 
which  these  bodies  break  under  certain  conditions,  the 
chemical  changes  to  which  they  are  subject  through  cer- 
tain agencies,  and  their  relation  to  one  another.  Investi- 
gations along  these  lines  have  for  years  occupied  the 
time  of  some  of  our  ablest  scientists,  and,  while  such 
researches  when  they  were  conducted  may  have  seemed 
to  the  extreme  utilitarian  to  be  of  little  value,  we  now  see 
how  directly  they  are  contributing  to  human  progress 
and  welfare. 

To  the  above  information  has  been  added  through 
physiological  investigations  a  knowledge  of  the  ways  in 
which  the  several  food  compounds  are  transformed  in 
digestion  and  in  other  metabolic  changes,  the  avenues 
along  which  these  compounds  travel,  and  the  ways  in 
which  their  products  of  decomposition  are  discharged 
from  the  animal  organism.  We  have  learned  how  to  dis- 
tinguish between  the  digested  and  undigested  food,  have 
demonstrated  that  all  the  nitrogen  of  the  decomposed 
proteins  passes  off  in  the  urine,  have  measured  the  com- 
bustion of  the  nutrients  and  have  learned  how  to  strike  a 
balance  between  the  income  and  outgo  of  the  animal 
body.  It  is  now  possible  to  determine  with  reasonable 
accuracy  just  how  much  substance  is  retained  or  lost 
from  the  body  of  the  experimental  animal  while  eating  a 
given  ration,  and  what  is  the  nature  of  the  gain  or  loss. 
Very  recently  means  have  also  been  devised  for  measur- 
ing the  heat  given  off  by  a  man  or  an  animal  in  order  to 
ascertain  the  actual  physiological  values  of  different 
feeding-stuffs. 

293.  More  accurate  methods  of  investigation  than 
practical  feeding  tests. — In  applying  the  principles  and 
facts  of  chemistry  and  physiology,  the  first  advance  from 


SOURCES  OF  KNOWLEDGE  207 

the  ultra-practical  feeding  experiment  in  the  direction 
of  an  accurate  history  of  what  occurs  when  the  animal 
is  eating  a  particular  ration  is  the  measurement  of  the 
digested  nutrients  and  the  determination  of  the  gain  or 
loss  of  nitrogen.  This  is  accomplished,  as  heretofore 
stated,  by  ascertaining  the  quantity  of  various  com- 
pounds eaten  and  the  amount  of  the  same  in  the  feces, 
the  difference  being  the  digested  portion.  The  urine  is 
also  collected,  and  if  the  nitrogen  in  it  is  less  or  more  than 
that  in  the  digested  protein,  then  the  animal  is  either 
gaining  or  losing  nitrogenous  body  substance,  unless 
the  measurement  is  with  a  milch  cow,  when  the  nitrogen 
in  the  milk  must  be  taken  into  account.  By  an  experi- 
ment conducted  in  this  way,  with  careful  and  continued 
weighings  of  the  experimental  animal,  it  is  possible  to 
secure  a  probable  relation  between  a  unit  of  digested  dry 
matter  and  a  unit  of  production.  Such  a  method  has  been 
used  to  determine  what  is  a  maintenance  ration  for  ani- 
mals of  several  classes,  and  in  those  cases  where  the 
experiments  have  been  continued  for  a  sufficient  length 
of  time  and  have  shown  on  repetition  a  reasonable  agree- 
ment, we  are  justified  in  accepting  the  results  as  a  close 
approximation  to  fact.  When  a  ration  keeps  an  animal  in 
nitrogen  equilibrium  for  one  or  more  months  and  no 
material  gain  or  loss  of  weight  occurs,  we  may  safely 
regard  it  as  approximately  a  maintenance  ration  under 
the  conditions  involved.  Experiments  of  the  same  kind 
are  equally  useful  in  testing  the  productive  power  of 
various  food  combinations,  and  whenever  by  such  con- 
tinued tests  one  ration  shows  no  superiority  over  another, 
it  is  safe  to  assume  that  no  differences  exist  which  would 
be  especially  important  to  the  farmer's  pocketbook.  This 
may  be  accepted  as  a  business  fact. 


208  THE  FEEDING  OF  ANIMALS 

294.  Studies  of  food  sources  of  animal  fats. — Another 
class  of  experiments  somewhat  more  severe  in  their 
requirements  are  those  designed  to  give  information  as 
to  the  relation  between  the  constituents  of  the  food  and 
the  growth  of  the  various  tissues  in  the  animal  body  or 
the  formation  of  milk  solids.  The  experiments  conducted 
by  Lawes  and  Gilbert  on  the  formation  of  fat  with  swine 
may  be  cited  in  illustration  of  the  methods  used.  These 
were  planned  so  as  to  learn  the  amounts  of  digested  pro- 
tein, carbohydrates,  and  fat  consumed  by  the  animal  and 
also  the  quantities  of  protein  and  fat  stored  in  the  body 
during  a  given  period.  "In  experiment  No.  1,  two  pigs 
of  the  same  litter,  of  almost  exactly  equal  weight,  and,  so 
far  as  could  be  judged  of  similar  character,  were  selected." 
One  was  killed  at  once  and  its  composition  determined, 
and  the  other  was  fed  for  ten  weeks  on  a  fattening  ration 
of  known  composition  and  then  slaughtered  and  analyzed. 
The  quantity  of  protein  and  fat  which  the  pig's  body  had 
gained  during  the  ten  weeks  as  ascertained  from  the  com- 
position and  weight  of  the  two  pigs  was  then  compared 
with  the  food-supply  of  similar  compounds.  It  was 
assumed  that  a  pound  of  food  fat  could  produce  a  pound 
of  body  fat  and  that  51.4  per  cent  of  all  the  protein  not 
stored  in  the  body  as  such  could  be  used  for  fat  formation. 
Even  with  the  most  liberal  allowances  it  was  found  that 
the  protein  and  fat  of  the  food  could  not  possibly  have 
been  the  sole  source  of  the  new  body  fat,  thus  forcing  the 
conclusion  that  the  carbohydrates  are  fat-formers.  Prac- 
tically the  same  plan  has  been  followed  in  studying  the 
source  of  milk-fat.  Several  cows  were  fed  on  carefully 
weighed  and  analyzed  rations  extremely  poor  in  fat,  and 
the  amount  and  composition  of  the  feces,  urine,  and  milk 
were  ascertained  during  sixty  to  ninety  days.  The  fat 


SOURCES  OF  KNOWLEDGE  209 

digested  from  the  food  and  the  theoretical  fat  equivalent 
of  the  decomposed  protein  as  measured  by  the  urine 
nitrogen  were  charged  up  against  the  milk-fat,  and  a  large 
quantity  of  the  latter  could  be  accounted  for  only  as 
having  had  its  source  in  carbohydrates. 

Another  method  of  investigating  fat  formation  has 
been  used  with  dogs.  It  is  well  known  that  when  an 
animal  is  deprived  of  food  the  expenditure  of  energy 
by  the  body  is  maintained  at  the  expense  of  body  sub- 
stance. Both  muscular  tissues  and  fatty  substance  are 
broken  down  and  used  in  this  way,  the  latter  being 
regarded  as  furnishing  the  most  natural  and  available 
supply  of  fuel.  It  was  found  in  the  case  of  dogs  that 
after  a  certain  number  of  days  of  starvation  there  oc- 
curred a  sudden  and  large  increase  in  the  waste  of  nitro- 
gen compounds  as  shown  by  the  urine  excretion,  the 
explanation  for  this  being  that  the  body  fat  had  become 
exhausted  and  a  demand  was  at  once  made  upon  the 
protein  tissues  for  the  necessary  supply  of  energy.  As 
soon  as  this  rise  of  nitrogen  waste  appeared,  then  the 
dog  was  allowed  to  eat,  and  whatever  fat  was  found  in 
the  body  at  the  end  of  the  feeding-period  was  regarded  as 
having  been  formed  from  the  food  taken  after  the  star- 
vation period.  If,  for  instance,  the  ration  was  wholly 
protein  and  fat  was  found  to  have  become  deposited  in 
the  body,  this  was  regarded  as  proof  of  the  formation  of 
fat  from  protein.  Such  experiments  as  these  have  not 
always  been  conclusive,  although  they  are  regarded  by 
some  scientists  as  having  furnished  proof  that  protein 
may  be  a  source  of  fat. 

295.  The  respiration  apparatus. — After  all,  the  investi- 
gations of  the  kinds  described  fail  to  furnish  data  so 
accurate  and  so  complete  as  are  necessary  for  entirely 

N 


210  THE  FEEDING  OF   ANIMALS 

safe  conclusions.  In  every  instance,  one  or  more  assump- 
tions are  involved  where  definite  proof  is  not  furnished. 
Nothing  short  of  a  complete  record  of  the  income  and 
outgo  of  the  animal  organism  during  the  experimental 
period  is  conclusive  evidence  as  to  whether  there  has  been 
a  gain  or  loss  of  body  substance  and  what  is  the  kind  and 
extent  of  the  growth  or  waste.  The  securing  of  such  a 
record  is  an  expensive  and  laborious  task.  It  requires  not 
only  complete  information  in  regard  to  the  quantity  and 
composition  of  the  food,  but  also  an  acccurate  measure- 
ment of  the  excreta,  including  the  feces,  the  urine,  the 
respiratory  products,  and  the  matter  given  off  through 
the  skin.  Such  measurements  are  taken  by  means  of  a 
respiration  apparatus,  a  costly  and  complicated  mechan- 
ism, a  detailed  description  of  which  would  be  of  little  use 
to  most  readers.  It  is  sufficient  to  state  that  this  appa- 
ratus makes  possible  the  collection  and  analysis  of  all  the 
excretory  products,  whether  solid  or  gaseous.  The 
experimental  man  or  animal  lives  in  a  closed  chamber 
into  which  is  introduced  food  and  fresh  air  and  from 
which  is  pumped  the  vitiated  air,  the  water  and  carbon 
dioxid  of  which  are  absorbed  and  weighed. 

All  conclusions  drawn  from  experiments  with  the 
respiration  apparatus  are  based  largely  upon  the  in- 
come and  outgo  of  nitrogen  and  carbon.  As  carbon 
is  a  constituent  of  all  possible  compounds  of  the  ani- 
mal body  except  the  mineral,  it  is  certain  that  when 
the  body  gains  in  carbon  it  gains  in  organic  substance 
of  some  kind,  and  if  it  loses  in  carbon  there  is  a  waste 
of  organic  body  substance.  The  general  character  of 
the  gain  or  loss  can  be  determined  by  the  nitrogen  bal- 
ance. If  more  nitrogen  is  taken  in  by  the  experimental 
animal  than  is  given  off,  it  is  clear  that  the  nitrogen 


SOURCES  OF  KNOWLEDGE  211 

compounds  of  the  body  have  received  an  accession. 
Knowing  as  we  do  the  proportions  of  nitrogen  and  car- 
bon in  the  various  tissues  of  the  animal,  we  can  calculate 
how  much  of  the  gain  or  loss  of  carbon  belongs  in  the 
nitrogenous  substance  deposited  or  wasted.  If  more 
carbon  is  gained  or  lost  than  can  possibly  be  associated 
with  the  nitrogen  gained  or  lost,  then  there  has  been  a 
gain  or  loss  of  fat,  because  protein  and  fat  being  the  main 
constituents  of  the  animal  carcass,  any  considerable 
retention  of  carbon  must  be  in  one  of  these  forms.  If 
there  has  been  nitrogen  equilibrium,  all  excess  or  deficit 
of  carbon  belongs  to  a  deposit  or  waste  of  fat.  By  such 
searching  methods  as  these,  it  is  possible  to  ascertain 
with  a  good  degree  of  accuracy  how  food  is  used  and  what 
quantity  and  kind  of  nutrients  are  needed  in  maintain- 
ing an  animal  under  given  conditions. 

296.  Determination  of  energy  values. — We  have 
reached  a  point  in  our  study  of  animal  nutrition  where 
we  realize  that  food  values  are  to  some  extent  commen- 
surable with  energy  values  and  that  it  is  desirable  to 
know  the  energy  product  of  different  compounds  and 
feeding-stuffs.  Moreover,  we  cannot  possess  sufficiently 
full  knowledge  concerning  the  energy  needs  of  the  several 
classes  of  animals  until  we  have  measured  energy  use  in 
terms  of  heat  given  off  under  the  various  conditions  of 
work  and  of  production.  The  mere  determination  of  the 
income  and  outgo  of  the  animal  body  does  not  neces- 
sarily measure  energy  needs  or  use.  We  may  go  so  far 
as  to  ascertain  that  a  certain  amount  of  carbon  from  a 
certain  source  was  consumed  in  a  given  time,  but  from 
this  alone  we  do  not  learn  the  extent  to  which  this  com- 
bustion has  supported  the  internal  and  external  work 
of  the  body. 


212  THE  FEEDING  OF  ANIMALS 

297.  Calculation  of  the  energy  value  of  a  ration. — 
Three  methods  may  be  adopted  for  determining  the 
energy  expenditure  by  an  animal  eating  a  given  ration. 
The  one  of  these  most  easily  carried  out  is  largely  a 
matter  of  mathematical  calculation.  By  the  use  of 
average  digestion  coefficients  it  is  possible  to  ascertain 
approximately  the  amounts  of  digestible  protein,  carbo- 
hydrates, and  fats  contained  in  any  ration  which  is 
apparently  accomplishing  a  desired  result.  We  have 
learned  from  previous  determinations  what  are  the  calorific 
values  of  individual  compounds  such  as  albumin,  starch, 
sugar,  stearin,  and  olein  and  these  compounds  are  assumed 
to  represent  the  energy  value  of  the  classes  of  nutrients  to 
which  they  belong.  If,  then,  we  multiply  the  calculated 
quantities  of  digestible  protein,  carbohydrates,  and  fats  by 
their  respective  assumed  energy  factors,  we  get  a  number 
which  has  been  taken  as  an  expression  of  the  available 
energy  of  the  ration  under  consideration.  This  method 
must  now  be  regarded  as  greatly  inaccurate,  because 
the  metabolizable  energy  of  the  digestible  material 
of  feeding-stuffs  is  found  to  be  much  below  the  calorific 
value  of  the  pure  nutrients  to  which  energy  measure- 
ments have  been  applied.  See  Tables  XXVIII  and 
XXXIII.  The  older  theoretical  method  by  computation 
might  give  the  relative,  but  not  the  actual,  units  of 
metabolizable  energy  in  the  several  feeding-stuffs,  for  the 
results  by  means  of  combustion  in  a  Zuntz  calorimeter 
of  pure  nutrients  do  not  measure  physiological  results 
with  complex  mixtures. 

298.  Energy  value  of  digested  nutrients. — A  second 
method,  which  is  probably  a  step  in  the  direction  of  greater 
accuracy,  is  to  determine  by  the  use  of  a  calorimeter  the 
heat  units  of  the  ration  and  also  of  the  urine  and  feces. 


SOURCES  OF  KNOWLEDGE  213 

The  differences  between  the  food  heat  units  and  those 
found  for  the  excreta  might  seem  to  represent  the  energy 
value  of  that  portion  of  the  ration  digested  by  the  animal. 
This  would  be  an  accurate  measurement  of  the  available 
or  metabolizable  energy  of  the  ration  if  it  were  not  for  the 
loss  of  unoxidized  gases,  chiefly  methane,  which  contrib- 
ute nothing  to  the  maintenance  of  the  animal.  Accurate 
work  requires  that  these  gases  be  measured.  But  even 
then  it  does  not  appear  to  what  extent  the  digested 
nutrients  have  been  oxidized  with  a  corresponding  radia- 
tion of  heat  or  whether  there  has  been  a  gain  or  loss  of 
body  substance.  If  there  has  been  a  gain  of  body  sub- 
stance, then  the  ration  is  productive,  but  if  there  has  been 
a  loss  of  body  substance,  then  the  ration  is  below  the 
required  standard  for  the  maintenance  of  the  particular 
animal  under  investigation.  In  a  study  of  energy  rela- 
tions, it  is  therefore  even  more  necessary  to  resort  to  a 
respiration  apparatus  of  some  sort  than  in  determining 
food  balances.  We  must  learn  the  actual  extent  of  the 
food  combustion  which  occurs  if  we  would  have  all  the 
data  necessary  for  measuring  energy  used,  and  here  we 
come  to  the  third  and  most  accurate  method  of  determin- 
ing energy  expenditure,  viz.,  experiments  with  a  respira- 
tion apparatus. 

299.  Measurement  of  food  combustion. — There  are 
two  general  ways  of  ascertaining  the  extent  to  which 
food  is  burned  by  any  living  organism.  One  is  to  measure 
the  products  of  combustion  and  the  other  is  to  measure 
the  amount  of  oxygen  used.  It  is  self-evident  that  no 
combustion  can  occur  without  the  use  of  oxygen,  and  so 
if  the  experimenter  is  able  to  learn  just  how  much  of  this 
element  is  taken  up  in  uniting  with  the  carbon  and  hydro- 
gen of  the  food,  he  has  a  direct  and  accurate  means  of 


214  THE  FEEDING  OF  ANIMALS 

measuring  actual  energy  production.  The  older  forms  of 
respiration  apparatuses  simply  allowed  an  estimation  of 
the  carbon  dioxid  and  water  given  off  by  the  animal. 
How  much  of  the  water  was  formed  by  the  oxidation  of 
the  hydrogen  of  the  food  and  how  much  was  simply 
evaporated  from  the  store  taken  in  as  water,  it  was 
impossible  to  know  by  direct  determination.  This  could 
only  be  calculated.  The  carbon  dioxid  was,  on  the  other 
hand,  a  direct  and  accurate  measure  of  the  combustion 
of  carbon.  Later  devices,  as,  for  instance,  the  one  used 
by  Zuntz,  allow  a  direct  determination,  not  only  of  the 
products  of  combustion,  but  of  the  oxygen  absorbed  by 
breathing.  This  method  of  work  seemed  to  have  advan- 
tages, as  one  measurement  not  only  checks  the  other,  but 
makes  it  possible  to  ascertain  the  actual  oxygen  consump- 
tion during  any  given  period  of  the  experiment,  as,  for 
instance,  when  the  animal  is  at  rest,  when  masticating 
food,  or  when  performing  a  given  amount  of  external 
work.  In  this  way,  Zuntz  made  his  masterly  demon- 
strations of  the  differences  in  oxygen  use  with  different 
foods  during  the  period  of  mastication. 

300.  Respiration  calorimeter. — None  of  the  older 
apparatuses,  whether  allowing  the  determination  of 
oxygen  consumption  or  not,  measured  the  heat  radia- 
tion from  the  animal  body,  or,  in  other  words,  the  amount 
of  energy  actually  evolved  from  internal  combustion. 
Professors  Atwater  and  Rosa  first  devised  a  respiration 
apparatus  which  was  at  the  same  time  a  calorimeter. 
The  quantity  of  heat  radiated  from  a  man  or  other 
animal  confined  in  this  calorimeter  is  absorbed  by  a 
known  volume  of  water  and  is  thus  determined.  This 
is  a  great  advance  towards  certainty,  because  direct 
measurements  of  the  energy  production  of  a  ration  are 


SOURCES  OF  KNOWLEDGE  215 

thus  made  possible  and  the  necessity  for  theoretical 
assumptions  is  largely  removed.  « 

301.  Study  of  the  efficiency  of  individual  proteins. — 
The  type  of  investigation  in  animal  nutrition  upon  which 
much  emphasis  is  now  placed  is  a  study  of  the  function 
and  relations  of  individual  compounds.  The  proteins 
have  been  especial  objects  of  studies  of  this  kind,  studies 
which  have  been  made  possible  through  the  isolation  and 
identification  of  many  individual  vegetable  and  animal 
proteins.  The  general  plan  of  work  has  been  to  feed  only 
one  well-identified  protein  in  connection  with  a  sufficient 
supply  of  all  the  other  nutrients  necessary  to  maintenance 
and  growth.  In  this  way  it  has  been  demonstrated  that 
the  individual  proteins  are  greatly  unlike  in  their  nutritive 
value  and  relations,  it  being  found  that  some  will  not 
sustain  growth  or  even  maintenance,  while  other  single 
proteins  constitute  an  efficient  protein-supply  for  any 
known  protein  use. 

It  is  already  made  clear  to  the  reader,  doubtless,  that 
the  demonstration  of  facts  and  principles  in  the  domain 
of  animal  nutrition  is  exceedingly  difficult.  It  should 
be  equally  clear  that  when  conclusions  are  reached  in  ways 
which  have  been  briefly  described,  they  are  worthy  of 
respect  and  should  have  greater  weight  than  the  neces- 
sarily imperfect  observations  of  common  practice.  Science 
often  errs  in  her  deductions,  but  the  efforts  of  her  workers 
are  constantly  directed  toward  the  elimination  of  false 
conclusions,  so  that  unsound  theories  are  not  likely  to  be 
accepted  for  a  great  length  of  time. 


PART  II 
THE  PRACTICE  OF  FEEDING 


CHAPTER  XIII 
CATTLE  FOODS— NATURAL  PRODUCTS 

THE  number  of  cattle  foods  now  available  for  use 
is  very  large,  and  the  list  appears  to  be  constantly  in- 
creasing. Not  only  have  several  fodder  plants  been 
added  to  those  formerly  grown,  but  we  have  now  a  great 
variety  of  waste  products  from  the  manufacture  of  oils, 
starch,  and  human  foods  that  are  being  placed  upon 
the  market  as  feeding-stuffs.  At  one  time  farmers  pro- 
duced all  their  cattle  ate,  and  this  was  done  without 
going  outside  a  very  limited  list  of  forage  plants  and 
grains.  All  this  is  changed,  especially  in  the  older,  more 
thickly-settled  portions  of  the  United  States,  so  that 
considerable  knowledge  is  now  needed  regarding  the 
composition  and  specific  characters  of  the  numerous 
kinds  of  feeding-stuffs  if  they  are  to  be  used  intelligently. 

302.  Classification  of  cattle  foods. — It  will  ajd  in 
discussing  this  branch  of  our  subject  if  we  first  note  the 
divisions  into  which  the  materials  used  for  feeding  farm 
animals  are  grouped-.  There  is  more  than  one  basis  upon 
which  it  is  possible  to  make  these  divisions — botanical 
relations,  the  portion  of  the  plant  used,  whether  stem  or 
fruit,  and  chemical  composition.  As  a  matter  of  fact,  all 
these  and  other  distinctions  are  involved  in  the  classi- 
fication of  the  cattle  foods  in  common  use  at  the  pres- 
ent time. 

The  feeding-stuffs  of  vegetable  origin  are  generally 
divided  into  four  classes:  (1)  Forage  crops,  consisting 

(219) 


220  THE  FEEDING  OF  ANIMALS 

of  the  stem  and  leaves  of  herbaceous  plants,  either  in 
green  or  air-dry  condition,  to  which  is  attached  in  some 
cases  the  partially  formed  or  wholly  mature  seed  or 
grain;  (2)  roots  and  tubers,  or  the  thickened  under- 
ground portions  of  certain  plants;  (3)  seeds  or  grains; 
(4)  parts  of  a  plant  which  are  the  by-products  from  the 
removal  of  other  parts  by  some  manufacturing  process. 
These  are  the  commercial  by-product  feeding-stuffs. 

FORAGE  FOODS 

303.  Classes  of  forage  crops. — The  valuable  forage 
plants  of  the  United  States  belong  mostly  to  two  families, 
the  grasses  (Graminese)  and  the  legumes  (Leguminosse). 
June  grass,  red-top,  timothy  and  the  cereal  grain  plants 
are    types    of    the    former;    and    the    clovers,    alfalfa, 
the  vetches,  and  peas,  of  the  latter.    Whether  in  the 
pasture  or  in  tilled  fields,  few  plants  outside  of  these 
divisions  contribute  materially  to  the  supply  of  high- 
class  fodders.    The  most  essential  difference  between  the 
members  of  these  two  families  of  plants  when  considered 
as  feeding-stuffs  is  the  larger  proportion  of  nitrogen  com- 
pounds in  the  legumes.   It  is  characteristic  of  all  legumes 
that  their  proportion  of  protein  is  high  as  compared  with 
any  other  forage  crops,   and  for  this  reason  they  are 
greatly  prized  on  dairy  farms.    The  fact  that  they  are 
regarded  as  increasing  materially   the  nitrogen  supply 
of  the  farm  from  sources  outside  the  soil  also  adds  to 
their  value. 

304.  Green  vs.  dried  fodders;  conditions  of  drying. — 
Nearly  all  of  the  herbaceous  plants  that  are  grown  for 
consumption  by  farm  animals  may  be  fed  either  in  a  green 
or  dry  state.   Oats,  maize,  clover,  alfalfa,  and  other  spe- 


CATTLE  FOODS— NATURAL  PRODUCTS  221 

cies  which  serve  so  useful  a  purpose  as  soiling  crops  for 
summer  feeding  are  also  dried  that  they  may  be  success- 
fully stored  for  winter  feeding,  although  mazei,  and,  to 
some  extent,  other  crops,  are  now  preserved  in  a  green  con- 
dition through  the  process  of  ensilage.  (See  Pars.  37-41.) 

305.  Effect  of  drying  fodders. — The  advantages  and 
disadvantages  of  green  as  compared  with  dry  fodders 
have  been  much  discussed.    It  is  safe  to  assert  that  the 
compounds   of  a   dried   fodder   which   has   suffered   no 
fermentation    are   practically    what    they   were   in   the 
green,  freshly  cut  material,  excepting  that  nearly  all  of 
the  water  contained  in  the  green  tissues  has  evaporated 
and  that  in  drying  there  is  a  possible  loss  of  an  imper- 
ceptible amount  of  volatile  compounds,  whose  presence 
in  the  plant  affects  its  flavor  more  or  less.    It  is  certain 
that  curing  a  plant  generally  diminishes  its  palatable- 
ness   and  increases  its   toughness,   or  its  resistance  to 
mastication,  although  with  many  crops,  as  for  instance 
the  early  cut  native  grasses,  these  changes  do  not  affect 
nutritive  value  to  a  material  extent.    There  is  no  ques- 
tion but  that  the  mere  matter  of  being  green  or  being  dry 
has  very  little  influence  upon  the  energy  value  of  a  fodder 
or  upon  the  extent  to  which  it  will  sustain  growth  or  milk 
formation.    We  must,  however,  take  into  account  the 
desirability  of  the  highest  state  of  palatableness. 

306.  Losses  through  curing  fodders. — Drying  fodders 
under  perfect  conditions  is  not  always  possible.    The 
long-continued  and  slow  curing  of  grass  in  cloudy  weather, 
especially  when  there  is  more  or  less  rainfall,  is  accom- 
panied by  fermentations  that  result  in  a  loss  of  dry  sub- 
stance more  or  less  extensive,  and  which  oxidize  some  of 
the  most  valuable  compounds,   principally  the   sugars. 
The  tissues  of  certain  plants,  maize  for  instance,  are  so 


222  THE  FEEDING  OF  ANIMALS 

thick  that  rapid  curing  in  the  field  is  never  possible,  and 
fermentative  changes  are  unavoidable.  It  is  probable 
that  maize  fodder  and  stover  are  never  field-dried  with- 
out a  material  loss  in  food  value,  for  it  is  found  that  even 
when  the  stalks  are  finely  chopped,  drying  by  artificial 
heat  is  necessary  to  a  complete  retention  of  the  dry  mat- 
ter. The  extent  of  the  loss  from  curing  fodders  must  be 
very  variable.  So  far  as  we  know,  grass,  which  in  "good 
haying  weather"  is  well  stirred  during  the  day  and  packed 
into  cocks  over  night  so  as  to  avoid  the  action  of  heavy 
dew,  suffers  practically  no  deterioration,  while  dull 
weather  or  rain  may  cause  a  serious  loss.  It  is  doubtful, 
however,  whether  night  exposure  during  good  weather  is 
sufficiently  injurious  to  justify  the  expense  of  cocking 
partially  cured  hay.  On  the  other  hand,  the  economy  of 
using  hay  caps  during  unfavorable  weather  is  without 
question.  The  over-drying  of  hay  before  raking  into 
winrows  and  "bunching"  so  as  to  cause  a  loss  of  the  leaves 
and  the  finer  parts  through  brittleness  may  be  as  wasteful 
as  under-drying  and  the  consequent  fermentation.  Over- 
dried  hay  does  not  pack  well  in  the  mow  and  is  less  pala- 
table. The  leguminous  hays,  such  as  clover  and  alfalfa, 
are  expecially  subject  to  loss  from  over-drying  before 
handling.  Fodder  crops,  if  dried  at  all,  should  be  dried 
to  such  a  percentage  of  moisture  that  they  will  not  "heat" 
to  discoloration  after  being  packed  in  large  masses  and 
lose  value  from  the  same  general  causes  that  operate  in 
field-curing  under  bad  conditions.  (See  Par.  45.) 

307.  The  harvesting  of  forage  crops. — The  result  to  be 
achieved  in  the  growing  of  forage  crops  is  the  produc- 
tion on  a  given  area  of  the  maximum  quantity  of  digesti- 
ble food  materials  in  a  palatable  form.  The  age  or  period 
of  growth  at  which  a  forage  crop  is  harvested  is  an  impor- 


CATTLE  FOODS— NATURAL  PRODUCTS 


223 


tant  factor  in  this  relation  and  may  affect  the  product  in 
three  ways:  (1)  in  the  quantity  of  material  harvested, 
(2)  in  the  composition  of  the  crop,  and  (3)  in  the  palata- 
bleness  of  the  resulting  fodder.  In  discussing  this  ques- 
tion we  must  recognize  the  fact,  first  of  all,  that  in  these 
respects  no  general  conclusion  is  applicable  to  all  crops. 
What  would  be  wisest  in  the  management  of  the  meadow 
grasses  might  be  wasteful  in  handling  the  legumes,  and 
especially  so  in  harvesting  maize. 

308.  Maximum  yield  of  forage  crops  at  maturity. — 
It  is  safe  to  assert  that  in  general  the  maximum  quan- 
tity of  dry  matter  is  secured  when  forage  crops  are 
allowed  to  mature  fully  and  ripen.  The  only  exception 
to  the  rule  is  found  in  the  legumes  such  as  the  clovers 
and  alfalfa,  where  at  maturity  the  leaves  unavoidably 
rattle  off  and  are  lost,  either  before  or  during  the  process 
of  curing.  The  fact  that  growth  of  dry  matter  takes 
place  up  to  the  time  of  full  maturity  is  well  illustrated  by 
the  results  of  experiments  conducted  on  the  farms  of  the 
Pennsylvania  State  College,  the  New  York  Experiment 
Station,  and  the  University  of  Maine,  in  cutting  timothy 
grass,  clover,  and  maize  at  different  stages  of  growth. 
These  results  are  summarized  in  the  accompanying  tables: 

TABLE  XLIV.   TIMOTHY  GRASS  (YIELD  OF  DRY  HAY  TO  THE  ACRE) 


Results  ir 

L   Maine 

Results  in  Pennsyl- 
vania —  two  farms 

Av.  3  years 
1878-1880 

1  year 
1889 

Av.  2  years 
1881-1882 

Nearly  in  head     .        

Pounds 

3,720 

Pounds 

Pounds 

Full  bloom       
Out  of  bloom  or  nearly  ripe 
Ripe       

4,072 
4,136 
3,832 

4,225 
5,086 

2,955 

3,501 

224 


THE  FEEDING  OF  ANIMALS 


MAIZE  FOR  SILAGE  (YIELD  OF  DRY  MATTER  TO  THE  ACRE) 


Stage  of  growth 

New  York 
1889 

Maine 
1893 

Tasseled  to  beginning  of  ear  

Pounds 

1,620 

Pounds 

3,064 

Silked  to  some  roasting  ears   
Watery  kernels  to  full  roasting-period  .    ...    .. 
Ears  glazing 

3,080 
4,640 
7,200 

5,211 
6,060 
6,681 

Glazed  to  ripe    .  >  V; 

7,920 

7,040 

RED  CLOVER  (YIELD  OF  DRY  MATTER  TO  THE  ACRE) 


Stage  of  growth 

Pennsylvania 
1882 

In  full  bloom      .>••;• 
Some  heads  dead                                                , 

Pounds 

3,680 
3,428 

Heads  all  dead 

3,361 

These  data  are  convincing  testimony  as  to  the  growth 
of  dry  substance  in  certain  forage  crops  up  to  and  in- 
cluding the  period  of  ripening.  Glover  is  an  apparent 
exception,  but  is  probably  not  really  so  because  after 
the  heads  begin  to  die  there  is  an  actual  loss  of  dry  mat- 
ter from  the  shedding  of  the  leaves. 

309.  Value  of  crops  not  proportional  to  yield. — It  does 
not  follow  when  a  plant  increases  in  its  yield  of  dry  matter 
that  its  nutritive  value  has  proportionately  increased. 
The  end  to  be  sought  is  the  largest  possible  quantity  of 
available  food  compounds,  and  it  is  entirely  possible 
that  changes  in  texture  and  in  the  composition  of  the 
dry  substance  may  partially  or  fully  offset  the  greater 
yield.  With  the  meadow  grasses  this  undoubtedly  hap- 
pens. The  dry  matter  of  mature  grass  contains  a  larger 
proportion  of  fiber  than  the  immature.  The  progressive 


CATTLE    FOODS— NATURAL    PRODUCTS 


225 


increase  of  fiber  as  the  plant  approaches  ripeness  is  well 
illustrated  by  analyses  made  at  the  Connecticut  Experi- 
ment Station  of  a  sample  of  timothy  grass  cut  at  different 
periods  of  growth : 

TABLE    XLV.      COMPOSITION  OF    DRY  SUBSTANCE    (PER  CENT) 


Stage  of  growth  of  timothy 

Ash 

Protein 

Crude 
fiber 

Nitro- 
gen-free 
extract 

Fats 

Well  headed  out  
In  full  blossom 

4.7 
4.3 

9.6 
7.1 

33. 
33.3 

50.8 
53.3 

1.9 

2. 

When  out  of  blossom      .    ... 

4.1 

7.1 

33.8 

53.3 

1.7 

Nearly  ripe       >   V 

3.6 

6.8 

35.4 

52.2 

2. 

These  analyses  show  that  the  changes  are  not  con- 
fined to  an  increase  of  fiber.  The  relative  proportions  of 
ash  and  protein  grow  less  as  the  plant  matures.  An 
examination  of  the  nitrogen-free  extract  would  prob- 
ably show  an  accompanying  decrease  of  the  soluble 
carbohydrates. 

The  combined  effect  of  these  changes  is  to  cause  the 
plant  to  harden  in  texture  and  become  less  palatable  and 
more  difficult  of  mastication. 

310.  Age  decreases  digestibility. — The  digestibil- 
ity is  naturally  affected  by  age.  Three  American  diges- 
tion experiments  with  timothy  hay  cut  in  bloom  or 
before  show  an  average  digestibility  of  the  organic  mat- 
ter of  61.5  per  cent,  the  average  from  four  experiments 
with  timothy  cut  when  past  bloom  being  55.4  per  cent. 
Doubtless  the  increase  in  dry  matter  when  timothy 
stands  beyond  the  period  of  full  bloom  no  more  than 
compensates  for  the  decrease  in  digestibility.  Using 
the  average  coefficients  of  digestibility  and  the  average 
yields,  as  given  in  this  connection,  the  yield  of  digestible 
o 


226 


THE  FEEDING  OF  ANIMALS 


organic  matter  would  be  in  full  bloom,  2,306  pounds,  and 
when  out  of  bloom  or  nearly  ripe,  2,350  pounds.  If  one 
considers  the  decrease  in  palatableness  the  advantage  is 
with  the  earlier  cut  hay. 

These  facts  do  not  pertain  to  timothy  alone.  Other 
meadow  grasses  are  similar  in  their  characteristics  of 
growth.  The  clovers,  and  especially  alfalfa,  deteriorate 
to  a  marked  degree  from  the  same  cause  when  allowed 
to  ripen  too  fully  before  cutting. 

It  is  probable,  all  factors  considered,  that  if  the  grasses 
and  clovers  which  are  cut  for  hay  could  be  harvested  when 
in  full  bloom  a  desirable  compromise  would  be  effected 
between  quantity  and  quality.  Alfalfa  should  be  cut  no 
later  than  when  the  first  bloom  makes  its  appearance. 

311.  Maize  unlike  other  grasses. — Conditions  are 
quite  different  with  maize.  This  plant  in  maturing 
gains  not  only  in  quantity  but  in  quality.  In  support  of 
this  statement  data  are  cited  from  an  experiment  con- 
ducted at  the  Maine  Experiment  Station. 

.  The  following  is  the  composition  of  the  dry  matter 
of  the  corn  when  cut  at  several  periods  of  growth: 

TABLE  XLVI.    IN  100  PARTS  WATER-FREE  SUBSTANCE  OP  MAIZE 


Total 

Stage  of  growth 

Ash 

Protein 

Crude 
fiber 

Sugar 

Starch 

nitro- 
gen-free 

Fat 

extract 

Very  immature,  Aug.  15    . 

9.3 

15. 

26.5 

11.7 

46.6 

2.6 

A  few  roasting-ears,  Aug.  28 

6.5 

11.7 

23.3 

20.4 

2.1 

55.6 

2.9 

All  roasting-stage,  Sept.  4 

6.2 

11.4 

19.7 

20.6 

4.9 

59.7 

3. 

Some  ears  glazing,  Sept.  12 

5.6 

9.6 

19.3 

21.1 

5.3 

62.5 

3. 

All  ears  glazed,  Sept.  21    . 

5.9 

9.2 

18.6 

16.5 

15.4 

63.3 

3. 

Here  we  see  the  same  decrease  in  the  proportions  of 
ash  and  protein  as  occurs  with  timothy,  but,  unlike 


CATTLE  FOODS— NATURAL  PRODUCTS 


227 


timothy,  the  maturing  of  the  maize  causes  a  decrease  in 
the  percentage  of  fiber  and  a  material  increase  in  the 
relative  amount  of  the  soluble  carbohydrates,  sugar, 
and  starch. 

These  data  give  us  every  right  to  expect  that  the 
dry  matter  of  the  mature  corn  plant  is  more  digestible 
than  that  of  the  immature  plant,  and  experimental 
tests  show  this  to  be  the  case.  There  follows  a  summary 
of  American  digestion  experiments  bearing  on  this  point: 

x*" 

TABLE   XLVIL     DIGESTED   FROM   100   PARTS  ORGANIC  MATTER 


Corn  fodder 

Corn  silage 

Max. 

Min. 

Av. 

Max. 

Min. 

Av. 

Cut  before  glazing,  13  experiments     .    .    . 
Cut  after  glazing,  10  experiments  .... 

71.4 

74.2 

53.6 
61.2 

65.7 
70.7 

77.8 
80.2 

56.6 
65.2 

67.4 
73.6 

The  advantage  is  seen  to  be  with  the  mature  corn. 
It  is  fair  to  conclude  from  all  these  observations  that 
harvesting  the  corn  plant  when  immature  is  injudicious 
from  every  point  of  view. 

312.  Alfalfa. — Alfalfa  has  become  in  many  parts  of 
the  United  States  one  of  our  most  important  forage  crops. 
Its  points  of  excellence  are  a  high  degree  of  palatableness, 
large  relative  yield,  its  partial  independence,  at  least, 
of  a  soil-supply  of  nitrogen,  and  its  efficiency  as  a  soil- 
renovating  crop.  From  three  to  five  cuttings  may  be 
made  annually;  and  the  yield,  according  to  records  in 
central  New  York,  sometimes  reaches  the  equivalent  of 
five  tons  of  hay.  The  fact  that  it  is  a  leguminous  plant 
indicates  a  useful  place  in  farm  cropping  because  of  the 
fact  that  the  percentage  of  protein  it  contains  is  consider- 
ably higher  than  that  of  the  true  grasses. 


228  THE  FEEDING   OF   ANIMALS 

In  order  to  successfully  establish  this  plant  in  many 
sections  it  is  necessary  to  inoculate  the  soil  with  the  bac- 
terium that  sustains  a  symbiotic  relation  with  this 
legume,  and  coapply  some  form  of  lime  when  the  soil 
has  a  high  degree  of  acidity. 

It  should  be  stated  that  the  relative  feeding  value  of 
alfalfa  has  been  overestimated  as  compared  with  other 
legumes,  such  as  the  clovers.  It  is  doubtful  whether 
alfalfa  hay  cut  and  cured  under  the  best  of  conditions  is 
superior  in  quality  to  the  best  quality  of  clover  hay. 

SILAGE 

About  forty  years  ago  a  new  process  for  preserv- 
ing crops  in  a  green  condition  was  introduced  into  the 
United  States,  viz.,  ensilage.  This  consists  in  storing 
green  material  in  receptacles  called  silos,  in  masses 
sufficiently  large  to  insure  certain  essential  conditions. 
Within  a  brief  period  after  maize  or  other  green  material 
is  packed  in  a  silo  the  mass  becomes  perceptibly  warm, 
and  in  the  course  of  two  or  three  days  it  reaches  its  maxi- 
mum temperature,  which  is  much  above  the  average  heat 
outside.  This  rise  hi  temperature  is  due  to  chemical 
changes  which  involve  the  consumption  of  more  or  less 
oxygen  and  the  production  of  compounds  not  previously 
existing  in  the  fresh  material. 

313.  Nature  of  the  changes  in  the  silo. — These  changes 
are  very  complex.  They  have  been  regarded  as  due  to 
the  activity  of  a  variety  of  ferments,  principally  those 
which  are  believed  to  cause  the  formation  of  alcohol 
and  acetic,  lactic,  and  other  acids.  Whether  the  oxida- 
tions occurring  in  the  silo  are  wholly  induced  by  ferment 
action  or  in  part  at  least  are  the  result  of  oxidations 


CATTLE  FOODS— NATURAL  PRODUCTS  229 

brought  about  in  other  ways  is  a  point  over  which  there 
has  been  some  recent  interesting  discussion. 

Babcock  and  Russell  carried  on  at  the  University 
of  Wisconsin  able  and  very  suggestive  investigations 
concerning  the  causes  of  silage  formation.  They  con- 
clude that  the  theory  that  silo  changes  under  normal 
conditions  are  due  wholly  to  bacteria  "does  not  rest  on  a 
sound  experimental  basis." 

Their  data  led  them  to  regard  respiratory  processes, 
both  direct  by  the  plant  cells  and  intramolecular,  as 
the  main  causes  of  the  chemical  transformations  which 
produce  carbon  dioxid  and  the  evolution  of  heat  within 
the  ensiled  mass.  The  direct  respiration  appropriates  the 
oxygen  confined  in  the  air  spaces  of  the  silo,  and  the 
intramolecular  respiration  uses  oxygen  combined  in  the 
tissues.  Both  forms  of  respiration  go  on  only  so  long 
as  the  plant  cells  remain  alive.  Concerning  bacteria 
the  authors  say:  "The  bacteria,  instead  of  function- 
ing as  the  essential  cause  of  the  changes  produced  in  good 
silage,  are  on  the  contrary  only  deleterious.  It  is  only 
where  putrefactive  changes  occur  that  their  influence 
becomes  marked." 

Doubtless  intramolecular  respiration  is  continued 
longer  in  immature  and  succulent  plant  tissues  than  in 
tissues  where  the  cells  have  reached  maturity,  and  so  the 
losses  in  the  silo  with  immature  plant  substance  are 
greater  than  with  mature.  Analyses  of  silage  from 
frozen  corn  and  feeding  trials  with  this  material  show 
that  it  is  not  economy  to  cut  immature  corn  for  fear  of 
frost,  as  the  increase  of  dry  matter  much  more  than  bal- 
ances the  loss  from  the  freezing. 

314.  Losses  in  silo. — Whatever  are  the  inducing 
causes,  a  careful  record  of  what  takes  place  in  the  silo, 


230  THE  FEEDING  OF  ANIMALS 

shows  that  the  silage  contains  considerably  less  dry 
substance  than  the  original  fresh  material.  Loss  occurs 
through  the  formation  of  volatile  products.  An  examina- 
tion of  the  fresh  corn  and  of  the  silage  shows  that  the 
latter  contains  much  less  sugar  than  the  former,  some- 
times none  at  all.  In  the  place  of  the  sugar  we  find  a 
variety  of  acids,  chiefly  acetic  and  lactic.  This  is  a  change 
similar  to  the  formation  of  acetic  acid  in  cider  and  lactic 
acid  in  milk,  in  all  cases  sugars  being  the  basal  com- 
pounds. Determinations  of  acidity  in  silage  by  Morse 
during  several  years  showed  it  to  vary  from  .8  to  1  per 
cent.  Along  with  the  development  of  these  acids,  carbon 
dioxid  and  water  are  formed  from  the  carbon  compounds 
of  the  ensiled  material.  In  other  words,  combustion  takes 
place  and  more  or  less  of  dry  matter  is  actually  burned 
up,  thus  generating  heat  and  causing  rise  of  temperature 
of  the  fermenting  mass.  The  amount  of  dry  matter 
thus  lost  is  determined  partly. by  the  kind  of  crops  and 
the  care  with  which  the  silo  is  built  and  filled. 

Another  important  chemical  change  induced  by  fer- 
mentation is  a  splitting  up  of  a  certain  portion  of  the 
proteins  of  the  fermenting  material  into  amino  acids, 
some  of  which  compounds  may  have  a  more  limited  nutri- 
tive function  than  the  proteins.  Investigation  conducted 
at  the  Pennsylvania  State  College  showed  that  in  some 
cases  over  half  the  nitrogen  of  silage  existed  in  the  amino 
acid  or  amide  form*  this  being  between  two  and  three 
times  as  much  as  was  found  in  the  original  fodder.  Proba- 
bly the  same  change  takes  place  in  the  field-curing  of 
fodder,  but  no  data  are  available  on  this  point.  Starch 
seems  to  resist  the  usual  silo  oxidations.  In  certain  experi- 
ments a  considerable  loss  of  nitrogen  is  reported.  It  is 
hard  to  understand,  though,  how  this  can  occur  to  any 


CATTLE  FOODS— NATURAL  PRODUCTS  231 

large  extent  unless  the  conditions  in  the  silo  are  very 
bad,  so  that  putrefactive  fermentations  set  in.  An  exten- 
sive loss  of  nitrogen  compounds  certainly  would  indicate 
very  serious  and  long-continued  destructive  changes. 

Steaming  the  corn  seems  to  depress  the  fermenta- 
tions and  decrease  the  percentage  of  acids  that  form. 
Knisely  found  .3  to  .88  per  cent  acidity  in  steamed  silage 
and  1  to  1.6  per  cent  in  unsteamed. 

315.  Corn  an  important   silo  crop. — The   nature   of 
the  changes  and  losses  in  producing  silage  have  been 
dwelt  upon  partly  because  corn,  the  principal  silo  crop, 
is  one  of  our  most  important  forage  crops,  perhaps  the 
most  so  on  a  dairy  farm,  and  partly  in  order  to  illustrate 
the  necessity  and  value  of  good  management  in  preserv- 
ing this  crop  by  the  silo  method.  Moreover,  the  loss  that 
is  incident  to  the  field-curing  of  maize  is  practically  the 
same  in  kind  and  is  fully  as  large  as  that  pertaining  to 
silage,  so  that  the  facts  presented  are  pertinent  to  both 
methods  as  well  as  to  all  circumstances  where  similar 
oxidations  and  fermentations  are  likely  to  ensue. 

316.  Extent  of  loss  in  the  silo.— The  extent  of  the  loss 
of  dry  substance  is  important.    It  measures  in  a  general 
way  the  difference  between  the  food  value  of  the  silage 
and  of  the  fresh  material.    The  silo  combustion  reduced 
the  energy  or  heat  value  which  the  fermented  fodder 
will  have  whenever  it  is   eaten  by  the  animal.     The 
heat  lost  would   supply  energy  to  an  animal  were  the 
combustion  to  occur  within  the  animal  instead  of  in  the 
silo.    It  is  desirable,  therefore,  to  know  the  extent  to 
which  dry  substance  is  actually  broken  up  in  the  prepara- 
tion of  silage.    This  loss  has  been  measured  by  several 
investigators,  and,  as  was  to  be  expected,  it  has  been 
found  to  depend  greatly  upon  the  conditions  involved, 


232 


THE  FEEDING  OF  ANIMALS 


the  figures  reached  varying  from  about  2  to  nearly  40 
per  cent  of  the  dry  matter  of  the  fresh  crop.  In  a  majority 
of  cases  the  loss  has  been  over  15  and  less  than  20  per 
cent.  King,  of  the  Wisconsin  Experiment  Station,  who 
gave  the  production  of  silage  much  study,  concluded 
upon  the  basis  of  his  observations  that  in  good  practice 
the  necessary  reduction  of  dry  matter  in  making  corn 
silage  need  not  exceed  4  to  8  per  cent,  and  with  clover 
silage  from  10  to  18  per  cent. 

317.  Necessary  loss  in  silo. — The  necessary  loss  is 
explained  as  being  that  which  occurs  in  the  interior  of 
the  mass  where  all  outside  air  is  excluded  and  other 
favorable  conditions  prevail.  Considering  the  contents 
of  the  silo  as  a  whole,  it  will  require  careful  attention  to 
all  details  in  order  to  reach  King's  estimate  with  the  best 
conditions  attainable. 

This  investigator  found  that  64.7  tons  of  silage  packed 
in  a  silo  lined  with  galvanized  iron,  thus  securing  a  per- 
fect exclusion  of  air,  lost  an  average  of  6.38  per  cent  of 
dry  matter.  This  silo  was  filled  in  eight  detached  layers, 
and  the  proportion  of  loss  in  these  several  divisions,  as 
affected  by  location,  is  most  suggestive : 

TABLE  XLVIII 


Silage 

Dry  matter 
lost 

Surface  layer 

Pounds 
8  934 

Per  cent 
32  53 

Seventh  layer    ....    .    
Sixth  layer 

8,722 
14661 

23.38 
1025 

Fifth  layer     .    . 

48*801 

2  10 

Fourth  layer  ...-.'..  \  :  .    
Third  layer    .    .    . 

13,347 

7723 

7.01 
2  75 

Second  layer  -,    . 

12,689 

3  53 

Bottom  layer 

12619 

9  47 

CATTLE  FOODS— NATURAL  PRODUCTS  233 

The  mean  loss  of  dry  matter  in  the  lower  six  layers 
was  only  3.66  per  cent.  These  figures  show  that  it  is 
profitable  to  make  the  walls  of  the  silo  air-tight,  even 
at  large  expense. 

318.  Financial  importance  of  silo  losses. — The  im- 
portance of  reducing  the  loss  in  the  silo  to  the  lowest 
possible  percentage  is  almost  self-evident.    As  this  point 
is  capable   of  mathematical  demonstration,   it  will  be 
interesting  and  suggestive  to  calculate  what  might  take 
place  in  a  hundred-ton  silo.    In  many  of  the  trials  which 
appear  to  have  been  conducted  under  not  unusual  con- 
ditions, a  loss  as  high  as  20  per  cent  of  the  dry  matter 
put  in  the  silo  has  been  observed.   In  a  hundred-ton  silo 
filled  with  corn  containing  25  per  cent  of  dry  matter,  or 
50,000  pounds,  this  would  amount  to  the  destruction  of 
10,000  pounds  of  dry  food  substance.    As  the  loss  falls 
chiefly  on  the  sugars  or  other  soluble  bodies  which  are 
wholly  digestible,  the  available  nutrients  in  the  fresh 
material  are  diminished  by  an  amount  of  digestible  dry 
matter  equivalent   to  what  would   be  required  by  ten 
milch  cows  during  two  months.    If,  therefore,  by  good 
planning  and  extra  care  this  waste  could  be  reduced  three- 
fourths  or  even  one-half,  the  food  resources  for  carrying 
a  herd  of  cows  through  the  winter  would  be  materially 
increased,  from  five  to  seven  and  one-half  tons  of  timothy 
hay  being  the  measure  of  the  saving  in  a  hundred-ton 
silo. 

319.  Ensiling  vs.  field-curing. — The  question  is  often 
raised  whether  ensilage  or  field-curing  is  the  more  waste- 
ful method  of  preserving  a  forage  crop.    Considerable 
study  has  been  given  this  matter,  and  the  results  secured 
have  been  taken  as  a  justification  of  the  statement  that 
one  method  is  about  as  economical  as  the  other,  which 


234  THE  FEEDING  OF  ANIMALS 

is  correct  if  we  consider  only  the  outcome  of  certain  com- 
parisons. A  general  survey  of  the  data  accumulated 
shows  that  on  the  whole  the  waste  has  been  the  larger 
in  field-curing.  Observations  made  in  six  states  reveal 
a  loss  by  the  old  method  as  low  as  18  per  cent  in  only 
one  case,  and  from  21  to  34  per  cent  in  all  others.  Pos- 
sibly under  favorable  conditions  of  weather,  field-cured 
corn  fodder  may  lose  as  little  dry  matter  as  silage,  though 
this  is  doubtful,  but  in  bad  weather  the  waste  from  the 
exposed  fodder  is  extensive.  The  greatest  advantage  in 
silo  preservation  is  that  conditions  can  usually  be  con- 
trolled with  more  satisfactory  average  results  than  are 
possible  in  field-curing.  Other  advantages  pertain  to  the 
silo  which  are  of  a  business  nature  and  which  need  not 
be  discussed  here  further  than  to  affirm  that  the  cost  of 
a  unit  of  food  value  is  in  general  diminished  by  the  use 
of  the  silo. 

320.  Crops  for  silage. — The  number  of  crops  that  may 
be  successfully  ensiled  is  not  large.  Maize  is  the  most 
valuable  one  for  this  purpose,  and  clover  and  alfalfa 
are  stored  in  this  manner  with  a  fair  degree  of  success 
although  silage  from  these  latter  crops  often,  if  not  gen- 
erally, carries  an  offensive  odor.  So  are  peas,  especially 
when  mixed  with  corn.  The  true  grasses  and  cereal 
grains  outside  of  corn  are  not  desirable  silo  crops,  first 
because  the  silage  from  them  is  generally  poor  in  quality, 
and  second  because  usually  they  may  be  successfully  and 
more  cheaply  stored  in  an  air-dry  condition.  Any  crop 
with  a  hollow  stalk,  giving  an  inclosed  air  space — oats, 
for  instance — is  not  adapted  to  silo  conditions,  and  there 
is  no  justification  for  ensiling  any  fodder  which  is  sus- 
ceptible of  prompt  and  thorough  drying  in  the  field, 
because  in  such  cases  there  is  an  unnecessary  waste  of 


CATTLE  FOODS— NATURAL  PRODUCTS  235 

food  substance  by  fermentation  and  an  unnecessary 
handling  of  many  tons  of  water  contained  in  the  green 
material,  with  no  compensating  advantages.  But  any 
crop  used  for  the  production  of  silage  should  be  managed 
in  the  most  efficient  manner.  A  few  general  facts  may 
be  discussed  in  this  connection. 

321.  Construction  of  silos. — Silos  that  are  of  proper 
construction  and  shape  have  air-tight  perpendicular 
walls  and  a  height  considerably  in  excess  of  either  of 
the  horizontal  dimensions.  These  conditions  are  essen- 
tial to  the  completest  possible  exclusion  of  air  and  to 
the  closest  possible  packing  of  the  material,  with  a  mini- 
mum of  exposed  upper  surface. 

Silos  may  be  either  round,  square,  or  rectangular, 
provided  that  in  the  latter  case  one  horizontal  dimen- 
sion is  not  too  greatly  in  excess  of  the  other.  The  shape 
of  a  silo  which  is  most  economical  and  efficient  is  not  the 
same  for  all  conditions,  although  the  round  and  square 
forms  hold  most  in  proportion  to  the  wall  area.  Many 
farmers  desire  to  have  the  silo  in  the  barn,  and  generally 
there  the  square  or  rectangular  form  is  more  economical 
of  space  than  a  round  one.  When  built  outside  the  barn, 
the  round  form,  according  to  the  opinion  of  many,  may 
be  used  to  advantage  both  as  to  expense  and  results.  If 
a  square  or  rectangular  silo  is  built  the  corners  should 
be  cut  off  inside  in  order  to  prevent  an  access  of  air  and 
the  decay  which  occurs  at  those  points  when  this  is  not 
done.  Several  kinds  of  materials  have  been  used  suc- 
cesfully  in  building  silos,  wood,  brick,  and  stone.  If  the 
walls  are  of  masonry  the  inner  surface  must  be  cemented 
not  only  air-tight  but  so  smoothly  as  to  allow  easy  and 
uniform  settling  of  the  silage  without  leaving  air  spaces. 
If  wood  is  used,  which  is  the  more  common  material,  the 


236  THE  FEEDING  OF   ANIMALS 

inside  construction  must  meet  the  same  requirements. 
Lining  a  wooden  silo  with  iron  has  been  suggested  as 
practical  and  economical.  Cement  is  used  successfully 
in  the  same  way.  Economy  demands  that  as  a  preventive 
against  decay  the  inner  woodwork  should  at  least  be 
treated  with  some  preservative,  which  may  also  serve  the 
purpose  of  obviating  excessive  swelling  and  shrinking  of 
the  lining  boards. 

322.  Filling  the  silo. — The  condition  of  the  crop  and 
the  manner  of  filling  a  silo  determine  to  a  great  extent  the 
character  of  the  silage.    Obviously  it  should  be  so  done 
as  to  reduce  the  loss  of  food  compounds  to  the  lowest 
possible  point.    Three  points  are  prominently  discussed 
in  this  connection:  (1)  the  condition  of  the  crops,  (2)  the 
preparation  of  the  material,  and  (3)  the  rate  of  filling. 

323.  Mature  corn  desirable  for  silage. — Experience 
has  thoroughly  demonstrated   that  the  maturity  of  a 
crop  influences  its  value  for  silage.   This  is  known  to  be 
especially  true  of  the  corn   crop.    An  immature  corn 
fodder,  which  always  carries  a  high  percentage  of  water 
with  less  of  the  matured  products,  such  as  starch,  is 
always  certain  to  change  to  very  acid  silage.    On  the 
contrary,  mature  corn,  when  properly  handled,  is  con- 
verted into  a  product  with  the  minimum  acidity  and  with 
an  appearance  and  aroma  much  superior  to  that  from  the 
immature  plant.   Neither  are  satisfactory  results  secured 
from  material  that  is  overdry.    It  may  be  stated  in  gen- 
eral terms  that  the  best  results  are  obtained  when  the 
proportion  of  dry  matter  falls  between  25  and  30  per 
cent.    If  corn  is  harvested  for  the  silo  after  the  kernels 
have  begun  to  glaze,  while  the  leaves  are  still  green  and 
before  they  show  dryness,  other  conditions  being  favora- 
ble, it  will  meet  every  requirement  for  good  silage. 


CATTLE  FOODS— NATURAL  PRODUCTS  237 

324.  Cutting    and    shredding    ensilage    material. — 
Whether  the  material  with  which  a  silo  is  filled  shall  be 
put  in  whole  or  after  cutting  or  shredding  depends  to 
quite  an  extent  upon  its  degree  of  coarseness.   It  is  prob- 
able that  clover,  and  even  the  smaller  varieties  of  maize, 
are  often  successfully  preserved  without  cutting,  but  no 
one  professes  that  this  can  be  done  with  the  coarser 
varieties  of  maize.    It  is  generally  admitted  that,  with 
maize,  cutting  or  shredding  it  increases  the  probability 
of  satisfactory  preservation,  because  the  finer  mechanical 
condition  allows  more  uniform  packing  and  prompter 
and  more  uniform  settling.    The  highest  grade  of  silage 
with  the  minimum  loss  is  undoubtedly  more  surely  made 
from  cut  or  shredded  material. 

325.  Rate  of  filling  silo. — In  the  early  days  of  silos  it 
was  taught  that  to  insure  the  least  possible  waste  by 
fermentation,  the  silo  should  be  filled  with  the  maximum 
rapidity  and  then  promptly  weighted.    Following  this 
view  was  the  conclusion  on  the  part  of  some  that  very  slow 
filling  with  no  packing  other  than  that  given  by  the  weight 
of  the  mass,  was  the  proper  way  to  make  silage  of  the 
highest  quality.   This  method  was  advocated  for  produ- 
cing sweet  (?)  silage.    It  allowed  violent  fermentation  at 
first  with  resulting  high  temperatures,  by  which  means 
bacteria   were    supposed   to   be   killed   and   subsequent 
fermentations  prevented,  a  conclusion  so  far  not  sus- 
tained by  scientific  observations.    Moderately  slow  and 
continuous   filling,    rather   than   very   rapid,    has   been 
advocated  by  leading  authorities.    Two  advantages  were 
claimed  for  this  method,  one  being  that  more  material 
can  be  stored  in  the  silo  and  the  other  is  that  silage  of  a 
higher  quality  is  produced  with  a  smaller  loss  of  dry 
matter.  The  first  point  must  be  conceded  and  the  second 


238  THE  FEEDING  OF  ANIMALS 

claim  may  be  true,  although  in  part  it  lacks  proof.  It  is 
hard  to  understand  why  slow  filling,  especially  if  inter- 
mittent, should  not  increase  rather  than  decrease  the 
losses  of  food  compounds.  Certainly  the  less  compact  the 
mass  the  more  intense  the  oxidation  and  the  higher  the 
temperature,  the  latter  condition  indicating  with  cer- 
tainty the  extent  of  the  combustion.  This  point  is  illus- 
trated by  results  reached  at  the  Pennsylvania  State 
College  when  the  chemical  changes  in  two  large  tubs  of 
sorghum  silage  were  studied,  one  of  which  was  com- 
pactly filled  and  weighted  at  once  and  the  other  loosely 
filled  and  weighted  after  five  days.  The  temperature 
rose  17°  higher  in  the  latter  than  in  the  former,  with  a 
loss  of  two  and  one-half  times  as  much  organic  matter 
from  the  loosely  filled  tub.  It  follows  from  the  theory  of 
Babcock  and  Russell,  previously  noted,  that  the  less  the 
oxygen  available  in  the  air  spaces  and  the  quicker  the 
plant  tissue  dies  the  less  will  be  the  combustion  or  loss 
of  organic  matter.  These  authors  suggest  as  a  prac- 
tical application  of  their  theory  that  the  air  be  excluded 
from  the  silo  as  rapidly  as  possible  and  only  mature  corn 
be  ensiled,  because  such  tissue  will  die  sooner  than  im- 
mature, having  less  vitality.  Their  data  seem  to  prove 
conclusively,  also,  that  the  evolution  of  much  heat  when 
a  fodder  is  first  ensiled  is  not  essential  to  the  formation 
of  first-class  silage.  The  repeated  exposure  of  a  loose 
upper  stratum,  which  occurs  with  slow,  intermittent 
filling,  must  cause  extensive  loss  from  portions  of  the  silo. 
It  must  be  held,  in  view  of  the  experimental  data  now  at 
hand,  that  the  more  promptly  the  air  is  excluded  and 
expelled  by  the  reduction  of  the  contents  of  the  silo  to  a 
condition  of  maximum  compactness,  the  less  will  be 
the  fermentation  losses.  The  term  "sweet  silage"  me  ins 


CATTLE  FOODS— NATURAL  PRODUCTS  239 

but  little  as  indicating  completeness  of  preservation,  for 
it  may  even  be  the  result  of  extensive  fermentations,  a 
condition  expensively  secured.  Its  significance  is  entirely 
different  when  the  sweetness  is  due  to  proper  maturity 
of  the  fodder  plant. 

THE  STRAWS 

326.  When    the    grain    plants    which    produce    seeds 
valuable  for  cattle  and  human  foods  are  threshed,  or 
in  some  way  manipulated  to  remove  the  seeds,  the  other 
parts  of  the  plant  constitute  what  we  call  straw  in  the 
case  of  the  cereal  grains  and   legumes,  and  stover  in 
the  case  of  maize.    These  fodders  differ  from  the  same 
plants,  when  cut  in  a  less  mature  condition  for  hay  or 
fodder,  in  being  more  tenacious  and  less  palatable,  with 
a  smaller  proportion  of  the  more  digestible,  and  there- 
fore more  valuable,  compounds.   The  most  useful  of  these 
materials  for  feeding  purposes  are  corn  stover,  oat  straw, 
and  the  legume  straws.   These  are  better  relished  by  farm 
animals  than  wheat  and  barley  straws,  which  are  utilized 
mostly  for  litter. 

ROOTS  AND  TUBERS 

327.  Certain  species  of  plants,  more  especially  beets, 
mangel-wurzels,   turnips,   rutabagas,   carrots,   and  pota- 
toes, are  agriculturally  valuable  because  of  the  store  of 
nutrients  which  they  deposit  in  subterranean  branches 
or  in  roots.    The  original  purpose  of  this  deposit  is,  in 
the  case  of  potatoes  and  artichokes,  to  nourish  the  young 
plants  of  the  next  generation,  or,  in  the  case  of  bien- 
nials like  beets,  to  supply  the  materials  for  the  seed- 
stalk  and  seeds  of  the  second  year.    Potatoes  are  not 
grown  primarily  as  food  for  cattle,  but  roots  have  for 


240  THE  FEEDING  OF  ANIMALS 

many  years  been  a  standard  crop  for  feeding  purposes. 
This  class  of  crops  has  the  advantage  of  furnishing  very 
palatable,  succulent  food,  which  may  be  kept  in  per- 
fect condition  during  the  entire  winter  season,  an  advan- 
tage which  is  not  wholly  measured  by  the  actual  quan- 
tity of  nutrients  supplied  by  these  materials. 

The  disadvantages  of  these  crops  are  that  they  are 
somewhat  expensive  to  grow  and  necessitate  the  hand- 
ling of  large  weights  of  water.  A  ton  of  turnips  or  man- 
gels may  furnish  even  less  than  200  pounds  of  dry  sub- 
stance, to  secure  which  1,800  pounds  of  water  must  be 
lifted  several  times.  The  percentage  of  dry  matter  in 
roots  and  tubers  varies  in  American  products,  on  the 
average,  from  9.1  per  cent  in  mangel-wurzels  and  tur- 
nips to  28.9  per  cent  in  sweet  potatoes.  Potatoes  are 
more  nutritive  pound  for  pound  than  roots.  The  dry 
matter  of  this  class  of  cattle  foods  is  principally  carbo- 
hydrate in  its  character,  though  the  proportion  of  pro- 
tein is  as  large  and  in  some  cases  larger  than  in  certain 
grain  foods. 

Two  conditions  are  essential  to  the  winter  storage  of 
roots  without  deterioration,  viz.,  a  low  temperature, 
as  near  freezing  as  possible,  and  abundant  ventilation. 
Large  masses  of  roots  un ventilated  are  apt  to  "heat," 
and  sometimes  decay,  with  a  resulting  large  loss  in  nutri- 
tive value. 

GRAINS  AND   SEEDS 

328.  The  conditions  which  provide  for  the  mainte- 
nance of  plant  life  also  subserve  the  interests  of  the  animal 
kingdom.  We  have  seen  that  this  is  true  of  the  store 
of  starch  and  other  compounds  in  tubers  and  roots, 
and  it  is  a  fact  of  much  larger  significance  in  the  produc- 


CATTLE  FOODS— NATURAL  PRODUCTS  241 

tion  of  seeds,  especially  those  of  our  cereal  grains,  includ- 
ing barley,  maize,  oats,  rice,  rye,  and  wheat.  Other 
seeds,  such  as  buckwheat,  cottonseed,  flaxseed,  beans, 
and  peas,  also  contribute  an  important  addition  to  our 
animal  feeding-stuffs.  In  all  these  species  there  is  de- 
posited in  the  seed  coats  and  either  around  the  chit  or 
embryo  or  in  the  seed  leaves  of  the  embryo,  a  store  of 
protein,  starch,  and  oil,  the  purpose  of  which  is  to  supply 
materials  for  growth  during  germination.  This  deposit 
of  plant  compounds  represents  the  highest  type  of  vege- 
table food,  whether  we  consider  concentration,  palatable- 
ness,  or  nutritive  efficiency.  Besides,  it  is  in  such  form 
that  with  ordinary  precautions  it  is  capable  of  indefinite 
preservation,  without  loss. 

329.  Storage  of  grain. — It  often  occurs  that  when 
newly-harvested  grain  is  stored  in  bulk  it  heats  and 
grows  "musty."  This  condition  is  due  to  fermentations 
that  are  made  possible  by  the  high  water-content  of  the 
fresh  grain  and  which  involve  a  loss  of  dry  substance.  It 
is  very  desirable  that  grain  shall  be  thoroughly  dried 
before  threshing,  and  it  is  generally  desirable  to  secure 
additional  drying  after  threshing  before  storing  it  in 
large  bins. 

The  agricultural  value  of  the  cereal  grains  is  much 
enhanced  by  their  adaptability  to  a  great  range  of  soil 
and  climatic  conditions.  They  are  the  American  farmer's 
great  reliance  for  the  production  of  the  highest  class  of 
cattle  foods.  Maize,  especially,  is  grown  from  Maine  to 
Florida  and  from  the  Atlantic  to  the  Pacific.  These 
crops  are  useful,  not  only  for  their  seeds  but  as  fodder 
plants.  For  soiling  purposes,  as  well  as  a  source  of  dried 
forage  they  are  highly  important. 


CHAPTER  XIV 

CATTLE  FOODS— COMMERCIAL  FEEDING- 
STUFFS 

THE  cereal  grains  and  other  seeds  are  the  source  of 
a  great  variety  of  by-product  feeding-stuffs  which  have 
a  large  and  widespread  use,  especially  in  the  dairy  sec- 
tions of  the  United  States.  In  the  preparation  of  a 
great  variety  of  human  foods  and  of  other  materials 
important  in  industrial  life,  certain  by-products  are 
obtained  which  represent  particular  parts  or  compounds 
of  the  grain  or  seed.  Whenever  the  methods  of  manu- 
facture are  such  as  not  to  injure  the  palatableness  or 
healthfulness  of  these  waste  products,  they  may  be 
utilized  as  cattle  foods.  As  a  matter  of  fact,  a  large 
proportion  of  our  commercial  feeding-stuffs  is  of  this 
general  kind  and  because  these  materials  differ  greatly 
in  composition  and  nutritive  value,  the  purchaser  should 
clearly  understand  their  source  and  character.  Changes 
in  methods  and  new  manufacturing  enterprises  are 
constantly  modifying  the  composition  of  old  products 
and  introducing  new  ones,  consequently  the  facts  as 
they  exist  at  one  time  may  not  be  applicable  for  a  long 
period.  There  is  need  therefore  of  constantly  keeping 
informed  in  regard  to  the  various  cattle  foods  found  in 
the  markets,  if  they  are  to  be  economically  purchased 
and  wisely  used. 

330.  Classes  of  commercial  by-product  feeding- 
stuffs. — For  the  purposes  of  description,  the  various 

(242) 


COMMERCIAL   FEEDING-STUFFS  243 

by-product   feeding-stuffs   may    be   classified    according 
to  their  origin.    Their  sources  are  mainly  as  follows: 

1.  The  milling  of  wheat  and  other  grains. 

2.  The   manufacture   of   oatmeal   and   a   variety   of 

breakfast  foods. 

3.  The  manufacture  of  beer  and  other  alcoholic  drinks. 

4.  The   manufacture   of   starch   and    sugars,   chiefly 

from  corn. 

5.  The  manufacture  of  beet-sugar. 

6.  The  extraction  of  oils,  chiefly  linseed  oil  and  cotton- 

seed oil. 

7.  Screenings  from  the  milling  of  wheat,  and  other 

refuses. 

8.  Compounded   feeds  made  up  from   a  variety   of 

by-products. 

331.  Wheat  offals. — No  commercial  feeding-stuffs  are 
regarded  with  greater  favor,  or  are  more  widely  and 
largely  purchased   by  American  feeders   than  the   by- 
products from  milling  wheat.    Wheat  bran  and  mid- 
dlings are  cattle  foods  of  standard  excellence,  whether 
we  consider  composition,  palatableness,  or  their  relation 
to  the  quality  of  dairy  products.    These  feeding-stuffs 
consist  of  particular  parts  of  the  wheat  kernel,  a  knowl- 
edge of  the  structure  of  which  aids  greatly  in  under- 
standing what  they  are  and  why  they  possess  certain 
chemical  and  physical  properties. 

332.  Structure    of    the    wheat    grain. — To    ordinary 
observation  the  wheat  grain  appears  to  be  merely  a 
seed,  but  it  is  really  a  seed  contained  in  a  tightly-fitting 
seed  pod.    This  pod,  which  is  woody  and  tough,  con- 
stitutes the  outer  coating  of  the  kernel.    On  the  seed 
itself  are  two  more  hard  and  resisting  coatings,  one  of 
which  is  double,  that  serve  to  protect  the  softer  parts. 


244 


THE  FEEDING  OF  ANIMALS 


We  find,  then,  that  in  every  wheat  kernel  there  are  three 
coats  entirely  unlike  the  rest  of  the  grain,  because  they 
consist  of  hard,  thick-walled  cells  containing  but  little 
starch,  if  any,  with  a  much  larger  proportion  of  cellulose 
or  fiber  than  is  found  in  the  inner  portion  of  the  kernel 
(Figs.  11  and  12.) 

Just  inside  the  innermost  of  the  three  outer  coats 
is  a  layer  of  material  very  rich  in  protein  compounds, 


FIG.  11.  Section  of  entire  wheat  kernel  (enlarged  16  diameters).  /, 
pod  and  seed  coatings;  4>  gluten  layer;  6,  mass  of  starch  cells. 


which  may  properly  be  called  the  gluten  layer.  The 
great  bulk  of  the  wheat  kernel  is  made  up  of  cells  closely 
filled  with  starch  grains.  This  is  the  soft  white  por- 
tion of  the  seed  and  is  that  which  furnishes  the  flour.  All 
of  these  parts  serve  to  protect,  and,  in  germination,  to 
nourish  the  essential  portion  of  the  seed,  the  germ  or 
embryo  which  lies  "at  the  lower  end  of  the  rounded  back 
of  the  kernel/*  Bessey,  in  an  admirable  description  of 


COMMERCIAL   FEEDING-STUFFS 


245 


the  wheat  kernel,  tells  us  that  the  percentage  propor- 
tions of  its  various  parts  are  as  follows: 


Per  cent 

Coatings 5          Starch  cells 

Gluten  layer 3-4          Germ     .    . 


Per  cent 

84-86 
6 


333.  The  milling  of  wheat. — We  are  now  prepared  to 
understand  the  significance  of  the  statement  that  in  mill- 
ing wheat  the  flour  of  various  grades  comes  from  the 
starch  cells,  the  other 
portions  passing  into 
the  bran,  shorts,  and 
middlings,  which  col- 
lectively are  termed  the 
offal.  If  only  the  coat- 
ings, gluten  layer,  and 
germ  went  to  make  up 
the  offal  it  would  in- 
clude only  about  14  or 
15  per  cent  of  the 
kernel,  the  flours  taking 
the  remainder,  but,  as 
a  matter  of  fact,  no 
milling  methods  so  far 
used  completely  separate  the  starch  cells  from  the 
inclosing  tissue,  so  that  the  offal  is  perhaps  never  less 
than  25  per  cent  of  the  whole  grain.  In  milling  tests  con- 
ducted by  the  Minnesota  Experiment  Station,  the  offal 
from  several  lots  of  wheat,  good  and  bad,  varied  from 
25  to  40  per  cent.  If  four  bushels  of  wheat  are  consumed 
per  capita  by  the  population  of  the  United  States,  which 
is  below  the  estimate,  and  if  only  one-quarter  of  this  is 
converted  into  offals,  the  amount  of  bran  and  middlings 
annually  consumed  by  our  domestic  animals  is  not  less 


FIG.  12.  Partial  scetion  of  wheat  kernel 
(enlarged  155  diameters).  1,  seed  pod; 
2,  outer  seed  coat;  3,  inner  seed  coat; 
4,  gluten  cells;  6,  starch  cells. 


246 


THE  FEEDING  OF  ANIMALS 


than  3,000,000  tons,  barring  the  quantity  which  may  be 
exported. 

334.  Composition  of  milling  products  of  wheat. — It 
is  a  fact  worthy  of  special  comment  that  because  of 
a  somewhat  irrational  standard  of  excellence  for  bread, 
certain  parts  of  the  wheat  kernel  best  adapted  to  the 
nourishment  of  young  and  growing  animals  are  separated 
with  great  care  to  be  used  by  the  brute  life  of  the  farm 
rather  than  by  the  farmer  and  his  family.  A  comparison 
of  the  composition  of  the  whole  wheat  kernel,  white 
flour,  and  the  various  parts  of  the  offal  emphasizes  this 
point.  The  figures  given  are  taken  from  the  results  of 
an  investigation  by  Snyder,  of  Minnesota,  in  which  he 
compared  the  composition  of  different  grades  of  wheat 
with  that  of  the  flour  and  products  obtained  from  them: 

TABLE  XLIX.    COMPOSITION  OF  WHEAT  AND  ITS  MILLING 
PRODUCTS  (PER  CENT) 


Water 

Ash 

Protein 

Fiber 

Nitrogen- 
free 
extract 

Starch 
and 
dextrine 

Fat 

Total 

Gluten 

Wheat  kernel  . 

10.2 

1.8 

13.7 

13.5 

3.2 

69. 

64.9 

2. 

Wheat  flour      . 

10.6 

.4 

11.2 

11. 

77.3 

70.4 

.5 

Wheat  germ 
Wheat  shorts    . 

10.4 
10.1 

2.7 
3.1 

15.7 
13.1 

15.3 
12.9 

5.4 

67.7 
65.3 

3.5 
2.9 

Wheat  bran 

10.4 

5.9 

15.4 

14.8 

10.2 

52.9 

5. 

The  greater  richness  of  the  coatings  of  the  kernel 
in  mineral  matter,  protein,  fiber,  and  oil  is  made  plain 
by  this  comparison.  There  is  four  times  as  large  a  per- 
centage of  mineral  matter  and  of  oil  in  the  whole  wheat 
as  in  the  flour,  nearly  one-third  more  protein  and  con- 
siderably less  starch.  On  the  other  hand,  the  bran  is  not 
less  than  ten  times  richer  in  mineral  compounds  and  oil 


COMMERCIAL   FEEDING-STUFFS  247 

than  the  flour,  one-third  richer  in  protein,  with  corres- 
pondingly less  starch.  "Graham"  flour,  which  contains 
more  or  less  of  those  parts  which  pass  into  the  offal  in 
milling  white  flour,  does  not  differ  so  much  from  the 
whole  kernel.  Middlings  differ  from  bran  in  containing 
less  of  the  hard,  tough  coatings  and  more  of  the  finer 
parts  of  the  kernels,  and  this  feeding-stuff  varies  from 
the  coarser  kinds  to  the  fancy  middlings,  according  to 
the  proportion  of  starchy  material  present.  Red  Dog 
flour  is  counted  among  the  offals  from  milling  wheat,  and 
it  represents  the  dividing  line  between  the  middlings  and 
the  high-grade  flour. 

335.  Milling  processes  compared. — There  is  a  belief 
more  or  less  prevalent  that  bran  from  the  old  milling 
processes  which  contained  more  of  the  starchy  part  of 
the  kernel  than  is  now  the  case,  was  more  valuable  than 
roller  process  bran  is.    It  is  probable  that  a  greater  pro- 
portion of  starch  increases  the  digestibility  of  bran,  and 
in  this  sense  the  old  process  bran  was  superior  to  the 
roller  process  product;  but,  on  the  other  hand,  the  latter 
is  more  nitrogenous  than  'the  former  and  is  therefore 
more  efficient  as  a  protein  supplement  to  home-raised 
foods. 

336.  Screenings. — Wheat,  when  sold  to  the  mills,  con- 
tains besides  inferior  wheat  grains  a  certain  percentage 
of  foreign  materials  such  as  other  grains,  weed  seeds, 
chaff,  bits  of  straw,  and  even  particles  of  grit.  Before  the 
wheat  is  milled  these  materials  are  removed  and  in  com- 
merce are  known  as  screenings.    While  the  percentage 
of  this  foreign  matter  in  wheat  is  small,  the  aggregate 
quantity  of  this  offal  put  on  the  market  is  very  large. 
Screenings  contain  ingredients  of  greatly  varying  qual- 
ity, some  of  which  are  very  inferior.   This  offal  is  almost 


248 


THE  FEEDING  OF  ANIMALS 


wholly  used  as  a  part  of  the  so-called  compounded 
feeds,  a  fact  to  be  reckoned  with  by  purchasers  of  these 
mixtures. 

Recently  millers  are  mixing  these  screenings  with  the 
bran.  Unquestionably  the  bran  thus  suffers  deteriora- 
tion proportionate  to  the  quantity  and  quality  of  the 
screenings.  The  guarantee  accompanying  such  mix- 
tures generally  specifies  "wheat  bran  with  the  mill  run 

of  screenings."  This  is 
a  part  of  the  growing 
practice  to  foist  upon 
the  consumer  a  great 
variety  of  by-products 
and  refuses,  some  good 
and  some  bad. 

337.  Residues  from 
breakfast  foods.  —  In 
the  manufacture  of 
breakfast  foods,  the 
use  of  which  has  be- 
come so  prevalent,  cer- 
tain by-products  are 
obtained  which  are  now  found  in  the  market  as  cattle 
foods.  The  preparation  of  oatmeal  and  similar  materials 
involves  the  selection  of  the  finest  oat  grains,  i.  e.,  those 
having  the  largest  kernels,  from  which  the  hulls  are 
removed.  These  hulls  and  the  smaller  oat  grains,  and 
perhaps  bran,  constitute  by-products  wrhich,  after  being 
finely  ground,  are  sold  as  oat-feed  and  in  various  mix- 
tures. As  the  sale  of  oat  hulls  as  such,  or  in  a  fraudulent 
way  when  mixed  with  other  substances,  is  likely  to  occa- 
sion a  financial  loss  to  feeders,  it  is  desirable  to  clearly 
understand  the  situation.  We  shall  accomplish  this  by  a 


FIG.  13.  Section  of  entire  oat  grain 
(enlarged  16  diameters).  0,  hull;  1,  seed 
coat;  4t  gluten  layer;  6,  mass  of  starch 
cells. 


COMMERCIAL   FEEDING-STUFFS 


249 


study  of  the  relation  of  the  oat  hulls  to  the  kernel  in 
quantity  and  composition.    (Figs.  13  and  14.) 

338.  The  oat  grain,  oat  hulls. — It  is  common  knowl- 
edge that  the  oat  grain  consists  of  a  hull  and  kernel, 
which  are  easily  separated.  The  former  is  fibrous  and 
tough,  and  the  latter 
soft  with  very  little  fiber. 
The  hull  forms  a  con- 
siderable portion  of  the 
grain.  In  1894,  the  Ohio 
Experiment  Station 
made  a  study  of  numer- 
ous varieties  of  oats.  It 
was  found  that  with 
sixty-nine  varieties  the 
hulls  constituted  from 
24.6  to  35.2  per  cent  of 
the  whole  grain,  the  aver- 
age being  30  per  cent. 
It  did  not  appear, -con- 
trary to  the  general 
opinion,  that  the  pro- 
portion of  hull  was  larger 
with  light  oats  than  with 
heavy,  although  observa- 


FIG.  14.  Partial  section  of  oat  grain 
(enlarged  170  diameters).  0,  hull;  1, 
seed  coat;  4,  gluten  cells;  5,  starch 
cells. 


tions  elsewhere  have  sustained  the  popular  view.  At  the 
Mustiala  Agricultural  College  twenty-eight  samples  of 
Finnish  oats  and  twenty  samples  from  five  other  coun- 
tries gave  from  28  to  32  per  cent  of  hulls.  Wiley  states 
that  the  average  proportion  of  hull  to  kernel  is  as  three 
to  seven,  which  varies  with  locality.  The  figures  in  the 
next  table  show  the  composition  of  the  dry  matter  of 
whole  oats,  oat  hulls,  and  the  hulled  kernel : 


250 


THE  FEEDING  OF  ANIMALS 


TABLE  L 


Ash 

Protein 

Fiber 

Nitrogen- 
free 
extract 

Fat 

Whole  oats,  30  samples  . 
Hulls,  New  Jersey               J. 

Per  cent 

3.4 

7.2 
6.9 
7.8 
2.3 

Per  cent 

13.2 
3.5 
4.4 
2.3 
15.4 

Per  cent 
10.8 
32. 

29.5 
50.1 
1.5 

Per  cent 

67. 
56.3 
57.2 
39. 
72.1 

Per  cent 

5.6 
1. 
2. 

.8 
8.7 

Hulls,  Vermont     .    .    .    .  \    ;. 
Hulls,  Wisconsin       .    .    ... 
Hulled  kernels,  179  analyses  . 

The  inferiority  of  the  hulls  as  compared  with  the  whole 
grain  or  with  the  hulled  kernels  is  very  apparent,  because 
of  their  smaller  proportion  of  protein  and  oil  and  their 
much  larger  percentage  of  fiber.  If  hulls  are  purchased 
at  all  the  price  should  be  on  a  par  with  that  at  which  the 
coarsest  and  cheapest  grades  of  fodders  are  sold. 

339.  Oat  clippings. — Oat  clippings  is  an  offal  intro- 
duced   into    the    market    at    a    later   date    than    oat 
hulls.    This    waste    consists    of    the    hairs,    oat    dust, 
and  light  oats  mostly  separated  from  the  oat  kernel  by 
the  clipping  process.    Such  material  is  inferior  both  as 
to  composition  and  digestibility.    It  is  now  much  used 
in  compounded  feeds.    Farmers  will  do  well  to  carefully 
inquire  into  the  character  of  the  so-called  oat  feeds  and 
compounded  feeds  offered  to  them.    These  articles  are 
often  oat  hulls,  poor  oats,  and  other  refuse  mixed  with 
corn  or  with  by-products  of  another  class  and  are  dis- 
tinctly inferior  to  the  whole    grains.     Such  low-grade 
mixtures  are  not  wisely  purchased  at  prices  nearly  equal 
to  those  ruling  for  whole  cereal  grains  of  any  kind. 

340.  Barley  feed. — This   is   a  by-product  from   the 
manufacture  of  pearled  barley,  and  like  oat  feed  consists 
of  the  hulls  and  portions  of  the  grain  and  contains  more 


COMMERCIAL   FEEDING-STUFFS  251 

fiber  and  less  starch   than  the  original  grain,  its  value 
being  proportionately  less. 

341.  Hominy  feed. — Hominy  is  made  from  corn  and 
consists  of  the  hard  portions  of  the  kernel,  leaving  as  a 
residue  the  hull,  germ,  and  part  of  the  starch  cells,  which 
collectively  are  sold  as  hominy  feed  or  chop.   This  differs 
from  the  whole  kernel  but  little  in  composition  and  is 
practically  as  digestible. 

342.  Brewers*  grains;    maltsprouts. — Sugar    in  some 
form  is  at  present  essential  to  the  production  of  alcoholic 
beverages,  a  cheap  supply  of  which  is  obtained  by  con- 
verting the  starch  of  certain  cereal  grains  into  maltose, 
which  afterward  passes  into  fermentable  sugars.    This 
result  is  accomplished  by  placing  barley  and  other  grains 
under  such  conditions  of  moisture  and  temperature  that 
they  germinate.    We  have  already  seen  that  during  ger- 
mination the  starch  of  a  seed  is  converted  into  maltose 
through  the  action  of  a  diastatic  ferment  (see  Par.  94), 
and  the   maltster  arrests   this  germination  at   a  point 
which  gives  the  maximum  quantity  of  sugar.    The  malted 
grains    are    subsequently   dried   and   the    sprouts    after 
removal  appear  in  our  markets  in  an  air-dry  condition, 
constituting  one   of    our   valuable  nitrogenous  feeding- 
stuffs.    The  malted  grains  are  then  crushed,  the  sugar  is 
extracted  from  them,  and  the  residue  is  known  in  com- 
merce as  brewers'  grains,  a  by-product  feeding-stuff  fairly 
rich  in  protein.    The  high  proportion  of  protein  is  due  to 
the   fact   that   the   starch   has   been   largely   removed, 
leaving  the  other  constituents  behind  in  a  more  concen- 
trated form.     These  grains  are  mostly  dried  and  may 
then  be  shipped  to  distant  markets  in  a  perfectly  sound 
and  healthful  condition. 


252  THE  FEEDING  OF  ANIMALS 

343.  Residues  from  starch  and  glucose  manufacture. — 
The  gluten  meals,  gluten  feeds,  corn  bran,  and  the  like 
are  residues  obtained  in  the  manufacture  of  starch  and 
glucose  from  the  maize  kernel.    This  kernel,  like  that  of 
wheat,  is  not  homogeneous  in  structure  and  composition, 
a  condition  which  makes  it  possible,  through  mechanical 
or  chemical  operations,  to  secure  a  variety  of  by-products 
greatly  unlike  in  texture  and  in    their  proportions  of 
nutrients. 

344.  Structure  of  the  maize  kernel. — All  this  is  made 
plain  through  a  consideration  of  the  structure  of  the 
maize  kernel.    This  seed  is  in  some  respects  similar  to 
that  of  wheat.    We  have  first  an  outside  husk  or  skin 
made  up  of  two  distinct  layers,  one  less  than  we  find  in 


FIG.  15.  Section  of  entire  maize  kernel  (enlarged  10  diameters).  1, 
outer  layer  of  husk  or  skin;  2,  inner  layer  of  skin;  4,  gluten  layer; 
6,  mass  of  starch  cells. 

wheat.  This  skin  is  rich  in  fiber,  scarcely  any  being  found 
in  the  other  portions  of  the  kernel.  Next  on  the  inside 
is  a  layer  of  cells  rich  in  gluten.  The  body  of  the  kernel 
surrounding  the  germ  or  embryo  consists  of  closely  com- 
pacted starch  cells,  though  some  of  this  interior  tissue  on 


COMMERCIAL  FEEDING-STUFFS 


253 


the  sides  of  the  kernel  next  to  the  walls  is  flinty.  We 
may  properly  speak  of  the  maize  kernel,  then,  as  consist- 
ing of  four  parts — the  husk,  the  gluten  layer,  the  germ, 
and  the  starchy  and 
hard  part.  (Figs.  15 
and  16.)  At  the  New 
Jersey  Experiment  Sta- 
tion one  hundred  grains 
of  the  maize  kernels 
were  separated  as  nearly 
as  possible  into  the 
skin,  germ,  and  main  or 
starchy  and  hard  por- 
tions. These  parts  were 
analyzed,  and  below 
is  given  their  compo- 
sition : 


16.  Partial  section  of  maize 
kernel  (enlarged  170  diameters).  /, 
outer  layer  of  skin;  2,  inner  layer  of 
skin;  4,  gluten  cells;  5,  starch  cells. 


TABLE  LI.   COMPOSITION  OF  DRY  SUBSTANCE  OF  MAIZE  KERNEL 
(PER  CENT) 


Ash 

Protein 

Fiber 

Nitrogen- 
free 
extract 

Fat 

Propor- 
tion 
of  parts 

Original  kernel  .  .  . 
Skin  
Germ  

1.7 
1.3 
11.1 

12.6 
6.6 
21.7 

2. 
16.4 
2.9 

79.4 
74.1 
34.7 

4.3 
1.6 
29.6 

100. 
5.5 
10.2 

Starch  and  hard  part. 

.7 

12.2 

.6 

85. 

1.5 

84.3 

These  figures  are  essentially  similar  to  those  obtained 
by  other  investigators,  including  Salisbury,  Atwater, 
and  Balland. 

345.  Manufacture  of  starch. — The  separation  of  starch 
cells  (see  Par.  102)  from  other  parts  of  the  kernel  is 
accomplished  mechanically.  Either  before  or  after  soak- 


254  THE  FEEDING  OF  ANIMALS 

ing  in  warm  water,  the  maize  kernels  are  crushed  into  a 
coarse  powder.  The  various  parts  separate  in  water  by 
gravity,  the  hulls  floating  on  the  surface  and  the  germs 
sinking  to  the  bottom.  The  starch  and  harder  portions 
of  the  kernel  remain  in  suspension  in  the  water,  which  is 
conducted  slowly  through  long  troughs,  where  the  starch 
settles  to  the  bottom  and  the  more  glutinous  portions 
float  off  and  are  recovered. 

It  is  now  easy  to  see  how  these  various  by-products 
may  differ  widely.  When  made  up  largely  of  the  hulls 
or  bran  they  are  characterized  by  a  relatively  high  pro- 
portion of  fiber  with  comparatively  low  percentages  of 
protein  and  fat.  The  presence  of  the  germs  increases  the 
relative  amount  of  protein  somewhat  and  of  the  fat  very 
greatly.  The  fine  glutinous  part,  that  is  finally  separated 
from  the  starch,  when  unmixed  with  other  materials  is 
distinguished  by  its  high  content  of  protein. 

As  found  in  the  market,  the  principal  brands  are  corn 
bran,  gluten  meal,  that  comes  from  the  flinty  portion  of 
the  kernel,  and  gluten  feed,  which  is  now  a  mixture  of 
hulls,  the  gluten  part,  and  the  steep  water  residue.  When 
unmixed  with  other  parts  of  the  kernel,  the  hulls  are  also 
known  as  corn  bran  and  the  germ  portion  from  which  the 
oil  has  been  pressed  is  called,  when  ground,  germ  oil  meal. 
The  corn  bran  contains  the  least  protein  and  the  gluten 
meal  the  most,  while  the  gluten  feed  and  germ  oil  meal 
occupy  a  position  between  these. 

In  recent  years  the  practice  has  been  adopted  of  add- 
ing to  the  gluten  feeds  the  solids  found  in  what  is  known 
as  the  steep  water,  that  is,  the  water  in  which  the  maize 
kernel  and  its  parts  have  been  soaked  during  the  process 
of  separation  of  one  part  from  another.  This  steep  water 
contains  all  that  is  soluble  in  the  maize  kernel  or  has 


COMMERCIAL   FEEDING-STUFFS  255 

become  so  through  the  treatment  it  receives,  including 
soluble  proteins,  amino  acids,  and  the  soluble  mineral 
salts  of  the  corn.  This  steep  water  residue  darkens  the 
color  of  the  feed  and  renders  it  acid  in  varying  degrees, 
which  at  first  caused  an  unwarranted  prejudice  against 
gluten  feeds  with  these  characteristics. 

346.  Residues  from  the  manufacture  of  beet-sugar. — 
An  industry  apparently  now  established  in  the  United 
States,  the  manufacture  of  beet-sugar,  is  offering  to 
farmers  two  waste  products,  sugar-beet  pulp  and  sugar- 
beet  molasses.  The  former  is  the  extracted  beet  tissue 
from  which  all  the  sugars  and  more  or  less  of  other  solu- 
ble compounds  have  been  removed.  This  pulp  as^  it 
leaves  the  factory  has  been  found  to  contain  an  average 
of  scarcely  10  per  cent  of  solids.  One  ton  of  pulp  sup- 
plies, then,  not  over  200  pounds  of  total  dry  substance, 
or  perhaps  160  pounds  of  digestible  dry  substance.  This 
means  that  it  would  require  six  tons  of  wet  pulp  to  supply 
as  much  of  digestible  nutrients  as  one  ton  of  good  hay. 
The  solids  of  the  pulp  must  be  regarded  as  inferior  to  those 
of  the  beets  before  extraction  because  consisting  more 
largely  of  fiber  and  gums  whose  productive  value  is  below 
that  of  sugar.  Experiments  at  Cornell  University  in- 
dicated that  the  pulp  is  worth  about  one-half  as  much 
as  corn  silage,  which  would  be  approximately  the  rela- 
tion of  digestible  matter  in  the  two  materials. 

Sugar-beet  pulpv  is,  however,  a  useful,  succulent  food, 
and  may  be  fed  to  advantage  in  quantities  from  seventy- 
five  to  one  hundred  pounds  daily  to  full-grown  animals, 
provided  it  can  be  purchased  at  a  price  proportional  to 
its  value. 

The  pulp  is  not  adapted  to  transportation  for  long 
distances  because  of  the  heavy  expense  of  freight  and 


256  THE  FEEDING  OF  ANIMALS 

handling,  but  is  most  available  for  consumption  near  the 
factories.  It  may  be  preserved  in  pits  or  silos. 

Dried  beet  pulp  is  now  on  the  market.  Its  protein- 
content  is  low,  and  the  carbohydrate-content  high.  The 
rate  of  digestibility  is  fairly  high.  Cattle-feeders  should 
bear  in  mind  that  the  use  of  this  material  only  intensifies 
the  already  high  carbohydrate-content  of  the  home-raised 
feeds. 

The  molasses  is  generally  four-fifths  or  more  dry 
substance  and  contains  from  40  to  50  per  cent  of  sugar, 
which  is  all  digestible  and  which  gives  to  this  product 
its  only  value  for  feeding  purposes. 

This  material  has  been  fed  successfully  to  bovines 
and  swine.  When  given  as  an  addition  to  coarse  foods 
and  home-raised  grains  it  obviously  should  be  combined 
with  some  nitrogenous  feeding-stuff  like  gluten  meal 
or  the  oil  meals. 

347.  The  oil  meals  in  general. — Materials  of  this  class 
may  properly  be  regarded  as  among  the  standard  feed- 
ing-stuffs. Because  of  their  uniformity  in  quality  and 
composition,  their  general  usefulness  in  compounding 
rations  and  their  value  in  maintaining  soil  fertility, 
their  use  has  had  the  sanction  of  scientific  men  and  of 
successful  practice.  The  oil  meals  are  so  called  because 
they  are  the  residues  left  after  the  extraction  of  the  oil 
from  certain  seeds  and  nuts,  among  which  are  cotton- 
seed, flaxseed,  hemp  and  poppy  seed,  rape  seed,  sesame 
seed,  sunflower  seed,  coconuts,  palm  nuts,  peanuts,  and 
walnuts.  Of  the  residues  from  these  sources,  those  from 
cottonseed  and  flaxseed  are  most  common  in  the  United 
States;  in  fact,  no  other  oil  meals  have  become  greatly 
important  in  our  cattle-feeding.  A  description,  therefore, 
of  the  production  of  cottonseed  meal  and  linseed  meal 


COMMERCIAL    FEEDING-STUFFS  257 

will  not  only  cover  the  points  of  practical  interest  to 
American  feeders,  but  will  serve  to  illustrate  the  main 
facts  that  pertain  to  the  manipulation  of  these  oil 
seeds. 

348.  Methods  of  extracting  oils. — It  may  be  stated 
in  a  general  way  that  two  methods  have  been  used  for 
removing  vegetable  oils  from  seeds,  expressing  by  pres- 
sure and  extraction  with  a  solvent.  With  the  first  method, 
it  was  formerly  the  custom  to  express  the  oil  from  the 
cold  crushed  seed,  but  now  the  seed  is  more  generally 
submitted  to  heat,  either  by  boiling  or  steaming,  after- 
ward applying  the  pressure  to  the  warm  material.   More 
oil  is  obtained  by  the  latter  process.    The  second  or 
extraction  method  involves  the  use  of  a  solvent,  gen- 
erally a  light  naphtha,  which  leaves  less  oil  behind  than 
either  cold   or   warm   pressure.     Before   extraction   the 
crushed  seed  is  heated  just  as  when  pressure  is  used. 

349.  Cottonseed  meal. — The  cotton  seed  as  gathered 
from  the  plant  consists  on  the  exterior  of  a  mass  of  long 
white  fibers  that  are  attached  to  the  outer  coat  or  hull, 
inside  of  all  of  which  is  the  kernel  or  meat.    The  seed 
is  first  delinted  by  running  it  through  a  gin,  which  removes 
the  lint  or  cotton  of  commerce.    After  this  operation 
there  is  still  attached  to  the  seed  a  soft  down,  which 
is  subsequently  removed  and  which  constitutes  what  is 
known  as  "linters,"  a  short  lint  that  is  used  in  making 
cotton   batting.      The    remaining  portion  is  that  from 
which  cottonseed  oil  and  certain  by-product  feeding-stuffs 
are  produced. 

350.  Cottonseed  hulls. — The  first  process  in  the  manu- 
facture of  the  oil  is  to  remove  the  hull  from  the  inside 
meat.    This  is  done  by  a  sheller,  which  breaks  the  seed 
coat  and  forces  it  from  the  kernel.    These  seed  coats, 

Q 


258  THE   FEEDING  OF  ANIMALS 

which  constitute  from  45  to  50  per  cent  of  the  delinted 
seeds,  are  known  in  commerce  as  cottonseed  hulls,  and 
are  used  to  some  extent  as  a  feeding-stuff.  They  are 
characterized  by  a  very  low  proportion  of  protein  and  a 
very  high  content  of  fiber.  Twenty-two  analyses  show  a 
range  of  protein  from  1.6  to  4.4  per  cent,  and  of  fiber 
from  35.7  to  66.9  per  cent.  Such  material  as  this  belongs 
with  the  very  lowest  grade  of  coarse  fodder,  as  both 
composition  and  experience  demonstrate. 

351.  Extraction  of  oil  from  the  cottonseed  kernels. — 
The  hulless  kernels  make  up  from  50  to  55  per  cent  of 
the  delinted  seed,  and  from  those  the  oil  is  obtained. 
These  meats  are  first  cooked  twenty  or  thirty  minutes 
in  large,  steam-jacketed  kettles  in  order  to  drive  off  the 
water  and  render  the  oil  more  fluid,  and  then  after  being 
formed  into  cakes  in  wire  cloths,  they  are  submitted  to  a 
pressure  of  3,000  to  4,000  pounds  to  the  square  inch. 
This  removes  at  least  four-fifths  of  the  oil  and  leaves  the 
cakes  very  solid,  which  after  drying  are  cracked  and 
ground  into  a  fine  meal,  known  in  commerce  as  cotton- 
seed meal.  Formerly  a  ton  of  ginned  seed  yielded  the 
following  quantities  of  the  different  parts: 

Pounds 

Linters 20 

Hulls    .   <..... 891 

Cake  or  meal      800 

Crude  oil 289 

Since  the  above  estimate  was  prepared  the  manufac- 
turing process  has  been  so  improved  that  from  forty 
to  forty-five  gallons  of  oil  are  now  obtained  from  a  ton 
of  seed,  giving  a  correspondingly  smaller  amount  of  cake. 
Cottonseed  meal  at  the  present  time  is  less  rich  in  oil 
than  was  the  case  a  few  years  ago. 


COMMERCIAL   FEEDING-STUFFS 


259 


352.  Composition  of  cottonseed  oil  by-products. — 
The  composition  of  the  cottonseed  oil  by-products  is 
the  following: 

TABLE  LII 


Nitrogen- 

Water 

Ash 

Protein 

Fiber 

free 

Fat 

extract 

Per  cent 

Per  cent 

Per  cent 

Percent 

Per  cent 

Per  cent 

Cottonseed     .... 

9.9 

4.7 

19.4 

226 

24. 

19.4 

Cottonseed  hulls   .    .    . 

11.4 

2.7 

4.2 

45.3 

34.2 

2.2 

Cottonseed  kernels    .    . 

6.9 

6.9 

30.3 

4.8 

21.4 

29.6 

Cottonseed  cake    .    .    . 

8.6 

7. 

44.1 

4.9 

21.2 

14.2 

These  figures  represent  the  composition  of  the  several 
materials  when  the  separations  are  fairly  complete. 
Cottonseed  products  are  sometimes  sold,  however,  in  a 
more  or  less  mixed  condition.  There  has-been  found 
in  the  market  undecorticated  cottonseed  meal,  or  the 
meal  with  all  the  hulls  ground  in  without  removal  from 
the  seed.  The  meal  that  is  free  from  hulls  should  be 
light  yellow  in  color  and  have  a  slightly  nutty  flavor.  It 
should  show  few  or  no  black  specks,  because  the  presence 
of  these  indicate  either  accidental  or  intentional  adul- 
teration with  hulls.  Cottonseed  meal  now  contains  less 
protein  than  was  formerly  the  case,  which  means,  un- 
doubtedly, that  a  larger  proportion  of  hulls  or  lint,  or 
both,  is  present.  Cottonseed  feed  is  a  finely-ground  mix- 
ture of  cottonseed  hulls  and  cottonseed  meal,  and  its  value 
is  less  than  that  of  the  pure  meal. 

353.  Linseed  meal  (oil  meal). — The  original  source  of 
this  feeding-stuff  is  the  flax  plant.  This  plant  serves 
a  very  useful  purpose  in  producing  a  valuable  fiber, 
and  oil  which  now  seems  indispensable  as  a  constituent 
of  paint  and  a  high-class  stock-food.  Flaxseed,  of  which 


260  THE  FEEDING  OF  ANIMALS 

the  annual  production  in  this  country  was  about  19,500,- 
000  bushels  in  1909,  contains  a  very  high  percentage  of  oil, 
ranging  in  the  analyses  so  far  made  from  22  to  40  per 
cent.  The  average  is  variously  stated  by  different  com- 
pilers at  from  33  to  37  per  cent,  and  the  mean  of  these 
two  numbers  is  probably  fairly  correct.  On  this  basis 
a  bushel  of  flaxseed,  weighing  fifty-six  pounds,  contains 
nineteen  and  one-half  pounds  of  oil  and  thirty-six  and 
one-half  pounds  of  other  substances. 

354.  Extraction  of  linseed  oil. — Linseed  oil  is  obtained 
from  the  seed  by  both  the  pressure  and  extraction  methods. 
The  oldest  method  was  to  subject  the  cold  crushed  seeds 
to  a  heavy  pressure,  which  expressed  from  70  to  80  per 
cent  of  the  oil,  leaving  a  cake  containing  from  10  to  15 
per  cent.    Later  the  warm  pressure  process  was  intro- 
duced, which  consists  of   moistening  the  crushed  seed, 
heating  it  to  from  160°  to  180°  R,  and  submitting  it  to  a 
pressure  of  2,000  to  3,000  pounds  to  the  square  inch.  This 
improvement  increased  the  output  of  oil  from  a  given 
quantity   of   seed,   the   amount   expressed   being    about 
90  per  cent  of  the  whole,  leaving  a  cake  containing  from 
6  to  7  per  cent.   The  latest  and  most  effective  process  is 
the  extraction  of  the  oil  by  a  light  naphtha.   The  seed  is 
crushed  and  heated  as  in  the  warm  pressure  method,  and 
the  oil  is  then  extracted  by  repeated  leachings  with 
naphtha  until  the  residue  when  dry  contains  only  about 
3  per  cent  of  oil.   The  naphtha  is  thoroughly  driven  from 
this  residue  with  steam  so  that  the  resulting  meal  is 
entirely  free  from  odor  and  is  as  palatable  as  the  residue 
from  the  pressure  process. 

355.  Old  process  vs.  new  process  linseed  meaL — 
The  terms  "old  process"  and  "new  process"  are  now 
applied  to  linseed  meal,  the  former  referring  to  that  made 


COMMERCIAL  FEEDING-STUFFS 


261 


by  the  cold  and  warm  pressure  processes,  and  the  latter 
to  the  residue  from  naphtha  extraction.  The  composi- 
tion differences  between  the  two  are  seen  in  the  following 
average  of  several  analyses  of  each  kind  which  were 
made  by  Woll : 

TABLE  LIII 


Nitrogen- 

Water 

Ash 

Protein 

Fiber 

free 

Fat 

extract 

Percent 

Percent 

Percent 

Percent 

Per  cent 

Percent 

Old  process  linseed  meal 

9.4 

5.4 

35.6 

7.1 

35 

7.5 

New  process  linseed 

meal    

9.2 

5.4 

36.6 

8.6 

37 

3.2 

These  averages  show  1  per  cent  more  protein  and  3 
per  cent  less  fat  in  the  new  process  meal. 

The  old  process  samples  analyzed  by  Woll  were 
doubtless  from  the  warm  pressure  methods  and  do  not 
fairly  represent  the  linseed  meal  which  was  found  in  the 
markets  when  it  first  came  into  general  use.  Four  hundred 
and  twenty-eight  analyses  of  old  process  cake  compiled 
by  Dietrich  and  Konig,  which  were  made  previous  to 
1888,  show  an  average  of  only  28.6  per  cent  of  protein 
and  10.6  per  cent  of  fat.  An  average  by  the  same  authors 
of  179  analyses  of  the  meal  shows  30  per  cent  of  protein 
and  9.9  per  cent  of  oil,  those  samples  taken  previous  to 
1880  being  poorer  in  protein  and  richer  in  fat  than  those 
analyzed  after  that  date.  The  average  of  twelve  samples 
of  linseed  cake  made  prior  to  1883  and  compiled  by 
Jenkins,  gives  29.7  per  cent  of  protein  and  11.2  per  cent  of 
fat.  There  is  no  question  but  that  the  meal  now  found  in 
the  markets  is  considerably  richer  in  protein  and  poorer 
in  fat  than  that  with  which  American  farmers  were  first 
acquainted. 


262  THE  FEEDING  OF   ANIMALS 

The  relative  values  of  the  old  and  new  process  meals 
are  much  discussed.  Many  farmers  are  prejudiced  in 
favor  of  the  former,  possibly  because  anything  which  has 
been  treated  chemically  is  regarded  with  suspicion  when 
considered  as  a  food.  No  good  evidence  exists,  however, 
that  new  process  meal  is  less  palatable  or  less  healthful 
than  the  old  process  product,  nor  has  practice  demon- 
strated that  in  a  general  way  it  is  less  nutritious. 

A  very  useful  inquiry  by  Woll  into  the  characteristics 
of  the  two  kinds  of  meal  showed  certain  differences  which 
are  interesting  in  this  connection.  Two  points  were 
studied:  the  digestibility  and  the  property  of  swelling  to 
a  mucilaginous  condition  when  stirred  up  with  water. 
Experiments  with  animals  both  in  Germany  and  in  this 
country  have  shown  a  quite  uniformly  lower  coefficient 
of  digestibility  for  the  protein  of  the  new  process  than 
for  the  old  process,  meal.  Woll  tested  this  matter  by 
artificial  digestion  with  a  solution  of  pepsin,  and  his 
results  verified  those  secured  with  animals,  the  protein 
of  the  old  process  sample  proving  to  be  10  per  cent  the 
more  soluble.  This  difference  is  believed  to  be  caused  by 
the  additional  cooking  with  steam  which  attends  the 
driving  out  of  the  naphtha  from  the  new  process  meal,  for 
it  seems  to  be  well  proven  that  the  digestibility  of  vege- 
table protein  is  diminished  by  cooking.  American  experi- 
ments do  not  indicate  a  lower  digestibility  of  total  dry 
matter  for  the  new  process  meal,  which  is  contrary  to 
the  verdict  of  German  digestion  trials. 

The  property  of  swelling  to  a  mucilaginous  condi- 
tion is  one  well  known  to  pertain  to  flaxseed.  This  is  due 
to  mucilage  cells  found  in  the  seed  coat.  When  this 
mucilaginous  matter  has  once  been  swollen,  it  will  not 
repeat  the  process  after  drying.  Woll's  tests  showed 


COMMERCIAL   FEEDING-STUFFS  263 

that  the  old  process  meal  responded  to  the  swelling  test, 
but  not  the  new  process,  a  result  due  probably  to  the 
steam  cooking  of  the  latter.  This  may  serve  as  a  means 
of  determining  the  method  used  in  manufacturing  a 
given  lot  of  meal,  but  probably  has  no  special  signifi- 
cance as  to  feeding  value,  unless  it  indicates  the  new  pro- 
cess meal  to  be  less  useful  in  making  a  porridge  for  feed- 
ing calves. 

CHEMICAL  DISTINCTIONS  IN   CATTLE   FOODS 

The  classes  of  cattle  foods  as  arranged  in  the  previous 
discussion  have  had  reference  to  several  factors,  chiefly 
those  relating  to  origin  and  texture.  Chemical  facts  have 
not  been  considerd  in  these  divisions.  There  are,  how- 
ever, certain  chemical  differences  among  the  various 
groups  of  feeding-stuffs,  a  knowledge  of  which  is  helpful 
in  selecting  materials  for  compounding  rations. 

356.  Coarse  foods  vs.  grains  and  grain  products. — In 
comparing  hays,  straws,  and  other  fodders  with  grains 
and  grain  products  there  are  points  of  chemical  unlike- 
ness  which  bear  an  important  relation  to  problems  of 
nutrition.  In  the  first  place,  the  nitrogen  compounds 
differ.  In  the  grains  we  find  the  nitrogen  combined  mostly 
in  the  form  of  true  proteins,  while  in  the  fodders  and 
roots  a  proportion  of  it,  and  sometimes  quite  a  large 
one,  exists  in  amides.  This  is  a  point  in  favor  of  the 
grains,  for  the  nutritive  function  of  amides  is  probably 
more  limited  than  that  of  the  true  proteins.  Again,  the 
non-nitrogenous  material  of  the  grains  is  in  general 
superior  to  that  of  the  herbaceous  cattle  foods.  In  the 
former,  especially  in  the  cereal  grains,  there  is  but  little 
fiber  and  the  nitrogen-free  extract  is  made  up  largely  of 


264  THE  FEEDING  OF  ANIMALS 

starch  and  other  bodies,  whose  net  value  in  nourishing  an 
animal  is  quite  surely  greater  than  that  of  fiber  and  gums 
found  in  such  abundance  in  the  hays  and  other  fodders. 
The  work  of  masticating  fibrous  materials  is  greater  than 
with  sugar  or  starch,  and  less  is  digested.  The  terms 
protein  and  carbohydrates  do  not  signify  the  same  com- 
pounds or  the  same  values  when  applied  to  different 
feeding-stuffs. 

357.  Classification  of  feeds  according  to  the  propor- 
tions of  nutrients. — The  relative  proportion  of  nitrog- 
enous and  non-nitrogenous   compounds  in  feeding-stuffs 
is  greatly  varied.    There  is  no  fixed  proportion  in  the 
same  species,  even,  but  it  varies  to  some  extent  with  the 
season,  period  of  cutting,  and  other  conditions.    At  the 
same  time,  there  are  differences  of  composition  between 
several  groups  of  feeding-stuffs  that  are  constant  within 
not  very  wide  limits,  and  which  it  is  important  to  recognize. 

358.  Misleading    terms    for    feeding-stuffs. — There 
are  a  few  terms  that  are  popularly  used  to  differentiate 
feeding-stuffs  which  are  misleading.    For  instance,  corn 
meal  is  often  spoken  of  as  "carbonaceous"  in  contrast 
to  cottonseed  meal,  which  is  called  "nitrogenous."  It  may 
be  seen  by  reference  to  preceding  data  that  there  is  a 
higher   proportion  of   carbon   in   the  proteins  than  in 
starch  or  sugars.    Cottonseed  meal  is  more  carbonaceous 
than  corn  meal,  rather  than  less  so.   Such  a  distinction  is 
therefore  absurd. 

"Heat-forming"  is  another  term  often  applied  to 
foods  rich  in  carbohydrates,  while  the  more  highly  nitrog- 
enous materials  are  characterized  as  "muscle-forming,"  a 
distinction  apparently  based  upon  the  facts  that  carbo- 
hydrates are  usually  largely  burned  in  the  animal  body, 
and  that  the  food  proteins  are  the  source  of  the  body 


COMMERCIAL  FEEDING-STUFFS  265 

proteins.  But,  as  a  matter  of  fact,  the  potential  heat 
value  of  the  digestible  part  of  an  oil  meal  is  certainly 
greater  than  that  of  digestible  corn  meal.  Under  certain 
conditions  one  feeding-stuff  is  no  more  fully  used  than 
the  other  for  tissue-forming  purposes,  and  both  may  be 
utilized  outside  of  the  usual  wastes  in  the  production  of 
some  form  of  energy,  ultimately  heat. 

359.  Classification  of  feeding-stuffs. — The  satisfac- 
tory division  of  feeding-stuffs  into  as  few  as  two  classes, 
according  to  their  composition,  is  not  possible  by  the  use 
of  any  terms  whatever.  Such  a  division  is  necessarily 
based  upon  the  relation  in  quantity  of  the  protein  to  the 
non-nitrogenous  part,  and  there  is  an  almost  uniform 
gradation  of  foods  in  protein-content  from  those  contain- 
ing the  least  to  those  most  highly  nitrogenous.  Any 
division  into  groups  with  reference  to  the  percentage 
amount  of  protein  must  be  entirely  arbitrary  and  should 
take  account  of  at  least  four  classes  of  materials,  other- 
wise the  extremes  of  each  division  are  too  widely  apart. 
Probably  no  more  convenient  and  rational  classification 
of  grains  and  grain  products  can  be  suggested  than  the 
one  proposed  by  Lindsey: 

Class  I.  Thirty  to  45  per  cent  protein,  30  to  45  per 
cent  carbohydrates.  The  oil  meals  and  gluten 
meals  and  certain  distillers'  dried  grains. 
Class  II.  Twenty  to  30  per  cent  of  protein,  60  to 
70  per  cent  carbohydrates.  Gluten  feeds,  the  lower 
grade  distillers'  dried  grains,  dried  brewers'  grains, 
maltsprouts,  buckwheat  middlings,  and  beans 
and  peas. 

Class  III.  Fourteen  to  20  per  cent  protein,  70  to  75 
per  cent  carbohydrates.  Wheat  brans  and  mid- 
dlings, rye  bran,  and  mixed  feeds. 


266  THE  FEEDING  OF  ANIMALS 

Class  IV.  Eight  to  14  per  cent  protein,  75  to  85  per 
cent  carbohydrates.  Barley,  corn,  oats,  rye,  wheat, 
cerealine,  hominy,  oat  feeds,  corn  and  oat  chop, 
and  corn  bran.  The  fodders  and  roots  properly 
belong  with  Class  IV. 

By  reference  to  these  groups  it  is  possible  to  ascer- 
tain about  what  place  a  particular  feeding-stuff  will 
take  in  making  up  a  ration,  for  instance,  to  what  extent 
it  will  serve  as  a  protein  amendment  to  a  mixture  of 
materials  composed  largely  of  carbohydrates. 

POODS  OF  ANIMAL  ORIGIN 

360.  The  principal  materials  of  animal  origin  that  are 
used  in  feeding  domestic  animals  are  milk,  dairy  by- 
products, and   offals   from   slaughter-houses.    They   are 
mostly  characterized  by  their  large  relative  proportion 
of  protein  and  their  high  rate  of  digestibility.    The  net 
nutritive  value  of  their  solid  matter  is  very  high,  because 
it  is  practically  all  utilized  and  a  minimum  amount  of 
energy   is  required   for   its   mastication   and   digestion. 
Practice  has  long  recognized  the  peculiar  efficiency  of 
feeding-stuffs  of  this  class,  which  is  due  to  the  directly 
available  forms  of  the  nutrients. 

361.  Milk. — Whole  milk  has  a  greatly  varying  food 
value  according  to  its  proportion  of  solid  matter.    Its 
composition  is  determined  by  several  factors.  The  milks 
of  different  species  of  domestic  animals  are  greatly  unlike 
both  in  their  proportions  of  total  solids  and  in  the  rela- 
tion in  quantity  of  the  different  constituents. 

The  table  of  the  average  composition  of  the  milk  of 
several  species,  given  herewith,  is  taken  mostly  from 
figures  given  in  Richmond's  "Dairy  Chemistry:" 


COMMERCIAL   FEEDING-STUFFS  267 

TABLE  LIV.   COMPOSITION  OF  THE  MILK  OF  MAMMALS  (PER  CENT) 


Species 

Water 

Dry  matter 

Ash 

Casein     Albumin 

Sugar 

Fat 

Bitch    
Ewe  

75.44 
79.46 

24.54 
20.56 

.73 
.97 

6.1              5.05 
5.23            1.45 

3.09 
4.28 

9.57 
8.63 

Sow      
Goat     

84.04 
86.04 

15.96 
13.96 

1.05 
.76 

7.23 
3.49              .86 

3.13 

4.22 

4.55 
4.63 

Cow*    . 

87.1 

12.9 

7 

3.2 

5.1 

39 

Woman    .... 

88.2 

11.8 

.2 

1.                  .5 

6.8 

3.3 

Mare    

89.8 

10.2 

.3 

1.84 

6.89 

1.17 

*Van  Slyke. 

The  milks  are  arranged  in  the  order  of  their  richness, 
the  dry  matter  present  varying  from  24.54  to  10.2  per 
cent.  Those  containing  a  high  proportion  of  total  solids, 
particularly  those  from  the  bitch  and  the  ewe,  are  espe- 
cially rich  in  proteins  and  fat,  the  percentages  of  sugar 
being  less  than  half  those  in  the  poorer  milks.  It  is  note- 
worthy that  the  proportions  of  proteins  and  fats  in  the 
milk  decrease,  and  the  percentage  of  sugar  increases,  as 
the  total  solids  diminish.  Two-thirds  of  the  solids  of 
mare's  milk  is  sugar,  the  proportion  of  this  constituent 
in  the  dry  matter  of  an  ewe's  milk  being  only  about  one- 
eighth. 

If  we  assume  that  the  milk  of  each  species  is  best 
adapted  to  its  own  progeny,  it  follows  that  when  the 
young  of  other  species  is  fed  the  milk  of  the  cow,  as 
is  so  often  done,  this  milk  should  be  modified  so  far 
as  possible  to  simulate  that  provided  under  natural  con- 
ditions. When,  for  instance,  cow's  milk  is  fed  to  a  colt, 
it  should  be  diluted  and  have  its  content  of  milk-sugar 
increased;  or  when  lambs  are  given  cow's  milk  it  may 
well  be  made  richer,  by  the  addition  of  cream,  perhaps. 


268 


THE  FEEDING  OF   ANIMALS 


362.  Milk  of  several  breeds. — The  milk  of  the  cow 
varies  with  the  breed,  the  individual,  and  the  period  of 
lactation,  and  in  its  use  for  feeding  purposes  these  varia- 
tions should  be  considered. 

TABLE  LV 


Ash* 

Solids 

Casein 

Albumin 

Sugarsf 

Fat 

Holstein-Friesian  .... 
Ayrshire  
Shorthorn  
Devon  
Guernsey  

.7 
.7 
.8 
.8 
,8 

11.8 
12.75 
14.3 
14.5 
14.9 

2.2 
2.46 
2.79 
3.1 
2.91 

.64 
.61 
.64 
.83 
.65 

5. 

5.22 
5.79 
4.88 
5.16 

3.26 
3.76 

4.28 
4.89 
538 

Jersey  

.8 

15.4 

3.03 

.65 

5.44 

5.78 

*Assumed. 


tCalculated. 


While  we  have  few  or  no  data  on  the  subject,  it  is 
probable  that  the  same  causes  operate  in  affecting  the 
milk  of  all  species. 

363.  Dairy  by-products. — These  by-products  are  three 
in  number,  skim-milk,  both  from  the  gravity  and  the 
separator  processes,  buttermilk,  and  whey.  Their  aver- 
age composition,  as  taken  from  compilations  by  several 
authors,  is  as  follows: 

TABLE  LVI.    COMPOSITION  OP  DAIRY  OFFALS  (PER  CENT) 


Water 

Total 
solids 

Ash 

Casein  and 
albumin 

Sugar 

Fat 

Skim-milk,  general  average,  Cooke 
Skim-milk,  gravity,  Fleischman  . 
Separator-milk,  Richmond  .  '  .  . 
Buttermilk,  Cooke  
Buttermilk,  Vieth  
Whey,  Cooke 

90.25 
89.85 
90.5 
90.5 
90.39 
92  97 

9.75 
10.15 
9.5 
9.5 

9.61 
7  03 

.8 
.77 
.78 
.7 
.75 
g 

3.5 
4.03 
3.57 
3. 
3.6 
93 

5.15 
4.6 

4.95 
5.3* 
4.06f 
5 

.3 

.75 
.1 
.5 
.5 
.5 

Whey,  Van  Slyke  

93.07 

6.93 

.65 

.83 

5.16 

.34 

*Probably  includes  the  lactic  acid,    f-80  per  cent  lactic  also  present.    §Assumed. 


COMMERCIAL   FEEDING-STUFFS 


269 


Skim-milk  and  buttermilk  are  not  greatly  unlike  in 
richness  in  solid  matter  or  in  general  composition.  In 
case  the  skim-milk  is  sweet,  buttermilk  differs  from  it 
because  in  the  latter  the  sugar  has  changed  partially  or 
wholly  to  lactic  acid.  Whey  is  considerably  poorer  in 
solids  than  the  other  dairy  by-products  and  also  differs 
from  them  in  the  proportions  of  the  several  constituents. 

Skim-milk  is  the  residue  left  after  removing  the 
cream.  It  differs  in  composition  according  to  the  com- 
position of  the  original  whole  milk  and  the  thoroughness 
of  the  creaming.  The  percentage  of  solids  which  it  con- 
tains is  proportional  in  a  general  way  to  the  richness  of 
the  whole  milk.  At  one  time  a  contrary  notion  prevailed 
and  the  skimmed  milk  of  the  butter  breeds,  especially 
the  Jersey  and  the  Guernsey  cows,  was  popularly  sup- 
posed to  be  of  inferior  quality.  Numerous  analyses  have 
been  made  of  this  by-product  from  several  breeds,  and 
the  succeeding  figures  give  the  proportion  of  solids  and 
fat  in  skimmed  milk  from  the  gravity  process: 

TABLE  LVII 


Solids  in 
whole  milk 

Skimmed  milk 

Total 
solids 

Fat 

Holstein    

Per  cent 
12.22 

12.98 
15.24 

Percent 

9.5 
10.4 
10.5 

Percent 

.52 
.85 
.37 

Ayrshire 

Jersey   

These  figures  show  most  clearly  that  the  Jersey  prod- 
uct is  more  valuable  than  that  from  Holstein  cows, 
volume  for  volume. 

Skim-milk  is  also  affected  by  the  manner  or  thorough- 


270  THE  FEEDING  OF  ANIMALS 

ness  with  which  the  cream  is  removed.  The  more  per- 
fectly the  fat  is  taken  out,  the  less  the  percentage  of  solids 
left  behind,  and  the  less  their  unit  value  as  a  source  of 
energy.  For  these  reasons  gravity-process  skimmed  milk 
is  often  more  valuable  for  feeding  than  that  from  the 
separator,  though  under  the  best  conditions  of  skimming 
in  both  cases  the  difference  is  small. 

Buttermilk,  which  is  the  residue  after  extracting 
butter  from  cream,  varies  in  composition  from  such  causes 
as  the  composition  of  the  cream  and  the  perfectness  of 
the  churning.  The  more  fat  that  is  left  in  it  the  more 
it  is  worth  for  feeding  purposes.  Its  feeding  value  is 
but  little  less  than  that  of  skim-milk. 

Whey  solids  are  mostly  sugar.  In  good  cheese-making 
practice,  whey  retains  scarcely  any  of  the  casein  and  fat 
of  the  milk.  It  therefore  takes  a  place  in  the  ration  quite 
different  from  that  of  skim-milk,  as  it  is  essentially  a 
carbohydrate  food. 

The  dairy  offals  are  peculiarly  valuable  as  food  for 
young  animals  and  swine.  It  is  safe  to  say  that  for  calves 
and  pigs  no  other  materials  can  fully  take  their  place 
in  their  relation  to  health  and  vigor. 

364.  Slaughter-house  and  other  animal  refuses. — The 
offals  from  slaughter-houses  and  from  fish,  which  have  a 
somewhat  limited  use  in  feeding  domestic  animals,  are 
meat  scraps,  meat  meal,  dried  blood,  and  dried  and  ground 
fish.  The  materials  serve  admirably  as  a  supplement  to 
the  home-raised  feeds  which  are  largely  of  a  carbohydrate 
character,  especially  in  feeding  poultry  and  swine.  In  the 
case  of  meat-scraps  it  is  desirable  to  distinguish  between 
those  having  a  large  proportion  of  bone  and  those  mostly 
meat.  The  accompanying  analyses  display  their  composi- 
tion, which  is  subject  to  great  variations: 


COMMERCIAL   FEEDING-STUFFS 


271 


TABLE  LVIII.     COMPOSITION   OF  SLAUGHTER-HOUSE  AND  OTHER 
REFUSES  (PER  CENT) 


Water 

Ash 

Protein 

Fat 

Animal  meal,  N.  Y.  station     .    .    .    f   . 

2.2 

38.7 

37.5 

13.2 

Meat  meal,  German  analysis      .    . 

10.7 

4.1 

71.2 

13.7 

Fish  scrap,  German  analysis  .    .    . 

13.9 

31.3 

48.4 

6.4 

Dried  blood,  Henry      

8.5 

4.7 

84.4 

2.5 

The  meat  and  fish  offals  vary  greatly  according  to 
proportion  of  bone  which  they  contain.  The  percentage 
of  protein  is  always  large,  nevertheless.  Dried  blood  is 
much  less  rich  in  mineral  matter  and  fat  than  other 
slaughter-house  offals  are  generally,  and  the  proportion  of 
protein  is  correspondingly  larger.  All  these  materials 
are  excellent  poultry  foods  when  used  as  a  part  of  the 
ration.  They  may  be  fed  to  swine  also  as  an  amendment 
to  cereal  grains  when  dairy  by-products  are  not  available. 


CHAPTER  XV 
THE  PRODUCTION  OF  CATTLE  FOODS 

THE  farmer,  in  deciding  what  forage  and  grain  crops 
he  shall  grow,  should  take  into  consideration  several 
factors,  of  which  the  following  are  the  main  ones:  (1) 
The  adaptability  of  the  various  crops  to  the  soil  and 
climate;  (2)  the  adaptability  of  the  various  crops  to  the 
kind  of  business  which  is  to  be  followed,  whether  dairy- 
ing, stock-growing,  or  sheep  husbandry;  (3)  the  capacity  of 
the  various  crops  for  the  production  of  digestible  food; 
(4)  the  protein  supply;  (5)  the  maintenance  of  fertility. 

365.  Adaptability  of  crops  to  environment. — Con- 
cerning the  adaptability  of  crops  to  the  great  variation 
of  soil  and  climate  in  this  country,  it  is  not  possible  to 
treat  extensively  in  this  connection  without  going  too 
fully  into  questions  of  agricultural  botany.  There  are, 
however,  a  few  general  facts  worthy  of  mention.  In  the 
first  place,  few  farmers  have  accurate  information  con- 
cerning the  species  of  grasses  which  are  growing  on  their 
farms.  Only  occasionally  is  one  found  who  carefully 
observes  what  species  are  most  prosperous  under  his  con- 
ditions. This  is  equivalent  to  the  statement  that  but 
little  attention  is  given  to  the  matter  of  the  adaptability 
of  forage  plants  to  the  environment  under  which  they 
must  be  grown.  While  it  may  be  said  that  nature  carries 
on  for  the  farmer  more  or  less  of  a  selective  process,  it 
must  be  remembered  that  the  rotation  of  crops,  involv- 
ing of  necessity  an  artificial  selection  of  species,  inter- 

(272) 


PRODUCTION  OF   CATTLE  FOODS  273 

feres  with  this  process.  The  old  practice  of  maintaining 
mowing  fields  for  ten  to  twenty  years  without  breaking 
the  sod  might  allow  the  grasses  most  congenial  to  the 
soil  and  climate  to  establish  themselves,  but  successful 
farming  on  this  basis  is  now  scarcely  possible.  It  is  essen- 
tial, therefore,  especially  in  dealing  with  meadows  and 
pastures,  to  know  what  members  of  the  grass  family 
or  other  forage  plants  find  the  environment  congenial. 

366.  New  vs.  old  species  of  plants. — It  is  commonly 
remarked,  with  much  reason,  that  more  is  to  be  gained 
by  the  proper  selection  and  proper  care  of  the  forage 
crops  which  have  maintained  successful,  though  perhaps 
unrecognized,  existence  among  us  for  years,  than  by  seek- 
ing for  better  results  from  some  introduced  species.    No 
cultivated  plant  possesses  qualities  that  will  defend  the 
farmer  against  the  evil  effects  of  poor  or  ill-directed  cul- 
ture, and  when  intelligent,  thorough  methods  prevail, 
many  of  the  familiar  species  will  do  for  us  all  we  can 
reasonably  expect.     Occasionally  an  introduced  species 
may  serve  a  useful  purpose,  as  is  true  of  alfalfa,  but  in 
general  a  more  economical  production  of  cattle  foods  will 
be   reached   most   surely   through   an   improvement   of 
methods  in  growing  what  we  already  have. 

367.  Adaptability  of  crops  to  kind  of  animal  produc- 
tion.— It  is  obvious  that  the  home  production  of  feed- 
ing-stuffs must  be  adapted  to  the  kind  of  stock  kept. 
A  herd  of  dairy  cows  can  hardly  be  most  successfully 
managed  on  the  old  basis  of  exclusive  pasturing  in  the 
summer  and  exclusive  dry  food  in  the  winter.   To  attain 
the  best  results  the  pasture  must  be  amended  by  soiling- 
crops,  at  least  during  late  summer  and  early  autumn,  and 
a  succulent  food  is  a  decided  improvement  to  a  winter 
ration.    On   the  other  hand,  the  successful  growing  of 

B 


274  THE  FEEDING  OF   ANIMALS 

steers,  sheep,  or  horses  requires  in  many  localities  only  a 
good  pasture  and  plenty  of  dried  fodder  and  grain, 
although  some  succulent  foods  are  desirable  with  any 
class  of  animals.  Every  feeder,  no  matter  what  his  line 
of  business,  should  have  at  command  quite  a  variety 
of  fodders. 

368.  Productive  capacity  of  crops. — The  productive 
capacity  of  the  different  crops  used  as  cattle  foods  is 
greatly  unlike.  A  satisfactory  crop  of  maize  or  alfalfa 
contains  greatly  more  dry  matter  an  acre  than  one  of 
oats,  peas,  or  any  of  the  usual  meadow  grasses,  and  in 
order  that  land  may  yield  a  maximum  supply  of  feeding- 
stuffs  it  is  necessary  to  step  outside  grass  and  grain  farm- 
ing, where  long  rotations  are  practised  and  where  a 
major  part  of  the  farm  is  kept  in  meadow  grasses  and 
only  small  areas  are  devoted  to  cultivated  crops.  Rapid 
rotation  and  the  use  of  the  more  grossly  feeding  crops 
are  necessary  to  a  vigorous  development  of  the  resources 
of  any  land  for  the  maintenance  of  animal  husbandry. 

Other  things  being  equal,  the  most  desirable  crop 
is  the  one  producing  the  largest  amount  of  digestible 
dry  matter.  This  will  not  be  the  same  crop  for  all  locali- 
ties. In  one  section  it  may  be  maize,  in  another  alfalfa, 
or  in  another  roots.  The  selection  must  be  determined 
by  circumstances,  and  no  rule  of  general  application  is 
possible.  Of  course,  other  things  outside  of  quantity  of 
production  are  not  generally  equal.  The  cost  of  pro- 
duction varies  so  that  the  largest  yielding  crop  is  not 
necessarily  the  most  economical.  This  is  a  local  matter 
also,  concerning  which  no  safe  general  statement  can  be 
made.  It  would  be  convenient  if  some  correct,  universal 
standards  of  production  and  cost  could  be  formulated 
for  the  guidance  of  farmers,  but  both  growth  and  cost  are 


PRODUCTION   OF   CATTLE   FOODS 


275 


much  modified  by  locality  and  other  circumstances  and 
data  are  not  available,  and  doubtless  never  will  be,  from 
which  useful  averages  may  be  obtained. 

The  most  that  it  is  possible  to  show  is  the  relative 
productive  capacity  of  different  crops  when  the  yield  is 
what  is  regarded  as  highly  satisfactory  in  favorable 
localities  under  good  culture.  This  is  done  in  the  accom- 
panying table.  Attention  is  again  called  to  the  fact  that 
judgment  should  be  based  upon  the  amount  of  digestible 
dry  matter  produced : 

TABLE  LIX 


Yield 

Dry 

Dry 

Digestible 

per  acre 
fresh 

Dry 

matter 

matter 
per 

matter 
digesti- 

dry 
matter 

material 

acre 

ble 

per 
acre 

Pounds 

Percent 

Pounds 

Percent 

Pounds 

Alfalfa    .  ,  

35,000 

25 

8,750 

69 

5,162 

Maize,  whole  plant      

30,000 

25 

7,500 

61 

5,025 

Red  clover,  about  3  ^  tons  new  hay 

18,000 

30 

5,400 

57 

3,070 

Oats  and  peas       

20,000 

16.2 

3,240 

65 

2,1,06 

Timothy,  about  2%  tons  new  hay 

11,500 

38.4 

4,416 

57 

2,517 

Hungarian  grass       

19,000 

25 

4,750 

67 

3,182 

Mangolds       

60,000 

10 

6,000 

88 

5,200 

Sugar-beets   

32,000 

20 

6,400 

88 

5,632 

Potatoes     

18,000 

25 

4,500 

85 

3,825 

The  estimates  here  given  may  not  coincide  with  the  views 
of  all  as  to  what  constitutes  a  fair  crop,  but  from  the  data 
shown,  anyone  can  easily  make  a  calculation  on  the 
basis  of  his  own  estimate. 

369.  Crops  of  high  productivity. — The  foregoing  figures 
emphasize  the  relative  high  productivity  of  alfalfa, 
maize,  and  roots,  as  compared  with  certain  cereal  grains 
and  the  meadow  grasses.  The  former  crops  fill  an  impor- 
tant place  in  intensive  stock  husbandry.  Probably  no 
species  of  forage  plants  are  known  that  are  more  economi- 
cal sources  of  high-class  cattle  food  than  alfalfa  and 


276  THE  FEEDING  OF  ANIMALS 

maize.  While  the  latter  crop  is  no  more  productive  than 
mangolds  and  sugar-beets  when  these  are  at  their  best, 
the  corn  crop  costs  much  less  in  labor. 

Crops  of  such  large  productive  capacity  are  espe- 
cially adapted  to  dairymen  located  on  limited  areas  of 
high-priced  land.  They  occupy  a  place  in  intensive  cul- 
ture which  will  become  more  and  more  important  as 
grazing  and  long  rotations  are  replaced  by  soiling  and 
stable  feeding  during  the  entire  year. 

370.  Home  supply  of  protein. — The  protein  supply 
of  the  farm  may  be  augmented  by  the  growth  of  legu- 
minous crops,  such  as  peas,  beans,  alfalfa,  and  the  clovers. 
In  so  far  as  climate  and  soil  permit  the  economical  pro- 
duction of  this  class  of  fodders,  there  will  be  a  corres- 
pondingly less  necessity  for  the  purchase  of  nitrogenous 
feeding-stuffs. 

371.  Legumes   and  fertility. — The  leguminous  crops 
are   regarded   as   sustaining   an   important   relation   to 
fertility  in  acting  as  nitrogen-gatherers,   and    for  this 
reason  they  are  believed  to  be  a  valuable  adjunct  of  any 
system  of  farming.    Just  what  proportion  of  the  nitro- 
gen in  a  crop  of  clover,  for  instance,  comes  from  outside 
the  soil  is  not  known,  however,  either  for  particular  con- 
ditions or  as  to  the  average. 

SOILING-CROPS 

372.  Soiling-crops   a   necessity. — The  production  of 
green  crops  as  an  amendment  to  the  pasture,  or  as  a 
substitute  for  it,  is  a  practice  essential  to  the  highest  suc- 
cess in  dairying  on  many  farms,  and  is  to  some  extent 
desirable  in  other  branches  of  stock  husbandry. 

There  are  few  pastures,   perhaps  none,   that  afford 


PRODUCTION   OF   CATTLE  FOODS  277 

grazing  in  August  and  September  of  such  a  quality  as  to 
maintain  a  satisfactory  flow  of  milk.  In  many  instances, 
moreover,  farmers  owning  a  limited  area  of  high-priced 
tillable  land  wish  to  keep  the  maximum  number  of  ani- 
mals an  acre,  and  to  do  this  they  must  cultivate  soiling- 
crops  for  stable  feeding. 

It  is  no  longer  a  debatable  question,  whether  or  not 
soiling  is  profitable  under  most  conditions.  Unlimited 
testimony  can  be  furnished  showing  the  great  gain  from 
every  point  of  view  of  even  partial  soiling  as  an  amend- 
ment to  the  pasture.  Whether  soiling  should  be  sub- 
stituted entirely  for  grazing  is  a  business  matter  which 
should  be  decided  according  to  the  conditions  involved. 

373.  Conditions  favorable  to  soiling. — New  England 
farmers  owning  upland  rocky  pastures  in  which  grow 
native  grasses  of  the  highest  quality  for  any  class  of 
animals  could  not  widely  discard  them.    Such  land  gen- 
erally absorbs  but  little  capital,  and  the  labor  of  supply- 
ing food  by  this  method  is  reduced  to  a  minimum.   The 
case  is  different  with  high-priced,  easily  tilled  land  located 
near  good  markets.    These  conditions  call  for  intensive 
farming,  and  grazing  animals  on  permanent  pastures  is 
not  a  part  of  intensive  practice.    Under  such  circum- 
stances the  wisdom  of  a  soiling  system  is  clearly  indicated. 

374.  The    economy    of    soiling-crops. — In    the    first 
place,  much  more  food  is  produced  on  a  unit  of  area  by 
soiling   than   by   pasturage.     Armsby   found   that   two 
soiling-crops  in  one  season,  for  instance  rye  followed  by 
corn,  yielded  five  times  as  much  digestible  organic  matter 
as  pasture  sod,  when  the  whole  growth  on  the  latter  was 
plucked  without  waste,  the  quantities  being,  respectively, 
5,845  and  1,125  pounds.    It  is  variously  estimated  from 
observations  in  practice  that  three  to  five  times  as  many 


278  THE  FEEDING  OF  ANIMALS 

animals  can  be  supported  on  a  given  area  by  soiling  as 
by  grazing. 

Again,  grazing  is  wasteful  because  of  the  imperfect 
consumption  of  the  growth  that  is  made.  Much  grass 
is  tramped  down  and  much  is  fouled  with  dung  and 
urine.  These  facts  are  well  understood.  Other  advan- 
tages besides  economy  of  land  and  material  pertain  to 
soiling,  such  as  saving  of  fences,  comfort  of  the  animals 
and  an  increased  supply  of  manure,  but  these  factors  do 
not  require  discussion  in  this  connection. 

375.  Selection  of  soiling-crops. — Outside  of  consid- 
erations previously  noted,  productiveness  especially,  the 
dairy  farmer  in  selecting  soiling-crops  must  have  regard 
chiefly  to  the  number  of  animals  to  be  fed,  the  time  when 
the  crops  will  be  needed,  and  the  number  of  days  required 
for  their  development.  If  soiling  is  adopted  in  order  to 
amend  the  pasture  during  the  late  summer  and  early  fall, 
a  limited  number  of  crops  will  meet  the  demand.  Three 
sowings  of  peas  and  oats  in  late  May  and  early  June  and 
two  plantings  of  corn,  one  at  the  usual  time  and  one  two 
weeks  later,  would  furnish  a  supply  of  green  food  when  it 
is  most  likely  to  be  needed.  If  it  is  a  question  of  selecting 
crops  for  a  system  of  complete  soiling,  nothing  more 
suggestive  can  be  offered  as  to  species  and  succession 
than  schemes  prepared  by  Phelps  for  Connecticut,  and 
by  Voorhees  for  New  Jersey: 


PRODUCTION  OF   CATTLE  FOODS 


279 


TABLE  LX 

Spec:es  of  crop                    1 
Winter  rye  
Winter  wheat     
Clover      
Grass  (from  meadows) 
Oats  and  peas     .    .    .    .    ; 
Oats  and  peas    
Oats  and  peas     

.    CONNECTICUT  SCHEME 

Approximate 
'ime  of  seeding            time  of  feeding 
Sept.  1                May  10-20 
Sept.  5-10          May  20-June  5 
July  20-30         June  5-15 
June  15-25 
April  10             June  25-July  10 
April  20              July  10-20 
April  30             July  20-Aug.  1 
June  1                Aug.  1-10 
Aug.  10-20 
May  25              Aug.  20-Sept.  5 
June  5-10          Sept.  5-20 
Sept.  20-30 
Aug.  5-10          Oct.  1-30 

JERSEY  SCHEME 

Approximate 
me  of  seeding              time  of  feeding 

Sept.                   May  1-10 
Sept.                   May  10-20 
Sept.                   May  20-June  1 
April  1                June  1-10 
April  10             June  10-20 
Sept.                   June  20-30 
May  10              July  1-10 
May  20               July  10-20 
June  1                July  20-Aug.  1 
June  20              Aug.  1-10 
June  10              Aug.  10-20 
June  20              Aug.  20-Sept.  1. 
July  10               Sept.  1-10 
July  20               Sept.  10-20 
July  1                 Sept.  20-Oct.  10 
Aug.  10              Oct.  10-20 
Aug.  20              Oct.  20-30 

Hungarian 

Clover,  rowen     
Soybeans 

Cowpeas      
Rowen  grass  (meadows)   . 
Barley  and  peas     .... 

NEW 

Species  of  crop                  Ti 
Winter  rye  
Winter  wheat 

Crimson  clover     ,  .  v  -  V  •  .  ••  ~ 
Oats  and  peas     .    .    .  ".   ,    ; 
Oats  and  peas    .    .    .    ;    . 
Mixed  grasses     .    .    .    ;  '-. 
Oats  and  peas 

Cowpeas      v  . 
Corn     . 
Japanese  Millet      .... 
Cowpeas      
Corn     
Soybeans     

Japanese  millet      .... 
Corn    

Barley  and  peas     .... 
Barley  and  peas     .... 

The  schemes  are  not  practicable  for  all  sections  of 
the  United  States.  In  the  southern  and  western  states 
more  especially,  they  would  need  modification  to  suit 
local  conditions. 

Alfalfa  is  not  included  in  either  of  the  foregoing  lists. 


280  THE  FEEDING  OF  ANIMALS 

For  all  sections  where  this  plant  can  be  grown  success- 
fully it  takes  first  rank  as  a  soiling-crop.  In  portions  of 
New  York,  for  instance,  in  favorable  seasons  it  can  be 
cut  continuously  from  about  the  last  of  May  until 
October,  and  no  other  crop  is  more  thoroughly  relished 
by  horses  and  cattle.  It  is  valuable  for  horses,  even  when 
they  are  doing  hard  work. 

376.  Soiling-crop  area  and  rotations. — The  area  de- 
voted to  soiling-crops  must  be  determined  by  the  num- 
ber of  animals  and  the  productiveness  of  the  land  which 
is  to  be  used.  Voorhees  states  that  seven  acres,  devoted 
to  the  succession  of  crops  which  he  recommends,  will 
supply  twenty-five  cows  from  May  1  to  November  1. 
This  estimate  would  hold  only  when  two  or  three  crops 
are  grown  on  the  same  land  in  a  single  season,  which 
requires  a  generous  use  of  manure  or  of  commercial  fer- 
tilizers, or  of  both.  The  following  are  suggestions  of  pos- 
sible rotations: 

/Winter  rye,  or  crimson  clover  /Winter  wheat 

<  Oats  and  peas  <  Cowpeas 
(Soybeans  (Japanese  millet 

/Oats  and  peas  /Oats  and  peas 

<  Japanese  millet  <  Cowpeas 
(Barley  and  peas  (Barley  and  peas 

(  Winter  rye,  or  winter  wheat  j  Crimson  clover 

/Corn  }Corn 

Some  writers  estimate  the  needed  area  of  soiling- 
crops  on  the  basis  of  one-quarter  to  one-half  a  square 
rod  a  day  for  each  full-grown  animal,  the  smaller  unit 
applying  to  corn  and  the  larger  to  oats  and  peas,  and 
similar  crops.  All  this  must  be  a  matter  of  judgment 
based  upon  the  circumstances  involved. 


CHAPTER  XVI 
THE  VALUATION  OF  FEEDING-STUFFS 

IT  seems  to  be  very  generally  supposed  that  it  is 
possible  to  state  fixed  relative  money  values  for  feed- 
ing-stuffs, and  that  by  comparing  these  with  market 
prices  the  relation  of  value  to  cost  may  be  ascertained. 
Such  a  state  of  knowledge  is  certainly  much  to  be  de- 
sired, for  it  would  be  of  great  practical  use  to  feeders. 
For  various  reasons,  however,  it  is  not  yet  attained, 
and  there  is  little  present  prospect  that  it  will  be.  The 
establishment  of  such  relative  values  for  cattle  foods, 
as  a  whole  and  for  general  use,  is  a  much  more  complex 
matter  than  many  suppose  it  to  be,  for  it  touches  on  one 
side  some  of  the  most  profound  problems  of  physiolog- 
ical chemistry,  concerning  which  we  have  only  partial 
knowledge. 

377.  Basis  of  assigning  values  to  feeding-stuffs. — 
The  problem  of  assigning  values  to  the  classes  of  nutrients 
in  feeding-stuffs  may  be  approached  from  two  directions, 
viz.,  from  the  commercial  side  and  from  the  physiolog- 
ical side.  In  the  first  case,  the  effort  would  be  to  calcu- 
late on  the  basis  of  the  prices  of  standard  commercial 
feeds  what  is  the  actual  pound-cost  of  each  of  the  classes 
of  nutrients,  and  thus  have  a  means  of  ascertaining 
whether  a  particular  feed  is  selling  for  less  or  more  than 
the  existing  market  conditions  warrant.  In  the  second 
case,  the  attempt  would  be  to  determine  the  relative 
physiological  importance  of  digestible  protein,  carbo- 

(281) 


282  THE  FEEDING  OF  ANIMALS 

hydrates,  and  fats,  and  this  being  done,  the  relative 
agricultural  values  of  feeding-stuffs  would  be  estab- 
lished on  the  basis  of  their  composition  and  digestibility, 
thus  providing  purchasers  with  a  guide  for  selecting  the 
materials  costing  the  least  in  proportion  to  their  value. 

378.  Commercial  values  of  feeding-stuffs. — Experi- 
ment stations  have  for  many  years  published  relative 
commercial  valuations  of  the  various  brands  of  fertilizers 
that  are  in  the  market.  We  are  not  able  to  establish  values 
similarly  with  cattle  foods  because  of  existing  condi- 
tions. The  dry  matter  of  cattle  foods  is  made  up  of 
ash,  protein,  carbohydrates,  and  fats.  We  practically 
ignore  the  ash  and  base  the  value  of  a  given  food  upon 
the  other  three  classes  of  compounds,  which  are  the 
same  in  number  as  the  three  useful  ingredients  of 
mixed  fertilizers.  Now  if  we  could  find  in  the  market  a 
cattle  food  supplying  only  a  single  ingredient,  as  is  the 
case  with  fertilizers,  we  could  from  its  composition  and 
market  price  determine  the  cost  of  this  ingredient.  As  a 
rule,  however,  these  classes  of  nutrients  must  be  bought 
in  a  mixed  condition.  All  commercial  cattle  foods,  except, 
perhaps,  one  waste  product  from  sugar  production,  are 
mixtures  in  varying  proportions  of  protein,  carbohydrates, 
and  fats.  When  we  buy  one  we  buy  all  three.  Protein, 
starch,  sugar,  or  oils  as  found  in  commerce  have  become, 
through  the  necessary  processes  of  separation,  too  costly 
to  be  considered  for  cattle-feeding  purposes,  and  their 
prices  in  these  forms  are  not  a  proper  basis  of  calculation. 
If,  therefore,  a  farmer  pays  $25  for  a  ton  of  wheat  bran, 
the  problem  would  be  what  proportion  of  this  sum  he 
should  assign  to  the  320  pounds  of  protein,  the  1,240 
pounds  of  carbohydrates,  or  the  84  pounds  of  fats. 

Commercially    considered    the    problem    is   complex, 


VALUATION   OF  FEEDING-STUFFS        S        283 

and  no  simple  process  will  solve  it.  If  we  were  to  deter- 
mine what  is  the  cost  of  one  pound  of  dry  matter  through 
the  simple  division  of  the  price  of  a  ton  of  feed  by  the 
pounds  of  dry  matter  which  it  contains,  and  then  declare 
that  all  forms  of  dry  matter  have  equal  cost,  we  would 
get  as  many  prices  for  protein  and  starch  as  there  are 
commercial  feeds,  with  no  distinction  as  to  the  money 
value  of  these  nutrients.  Such  a  method  would  be  absurd. 
It  would  be  a  bare  assumption  to  declare  that  all  the 
compounds  of  a  food  should  have  equal  market  cost. 

379.  Valuation  of  feeds  by  method  of  least  squares. — 
An  attempt  was  made  in  Germany,  and  to  some  extent 
in  this  country,  to  calculate  by  the  "method  of  least 
squares"  what  should  be  considered  the  cost  of  protein, 
carbohydrates,  and  fats  as  based  upon  the  ton  prices  of  a 
variety  of  feeding-stuffs.  Valuations  so  derived  appeared 
to  find  favor  for  a  time,  and  some  of  our  experiment 
stations,  following  the  lead  of  German  chemists,  pub- 
lished pound  prices  for  the  three  classes  of  nutrieftts, 
and  calculated  what  commercial  cattle  foods  should  cost 
when  valued  on  a  common  basis.  It  was  soon  found,  how- 
ever, that,  mathematically  as  well  as  practically,  most 
absurd  results  were  obtained. 

In  the  first  place,  it  is  already  demonstrated  that 
the  money  valuations  are  often  greatly  influenced  by 
the  choice  of  feeds  which  shall  enter  into  the  calcula- 
tion. Penny,  in  New  Jersey,  using  cottonseed  meal, 
bran,  middlings,  cob  meal,  corn  meal,  and  oats,  obtained 
certain  values  for  protein,  carbohydrates,  and  fats.  Hills 
showed  that  if  Penny  had  left  out  the  cob  meal  the  value 
for  fat  would  be  only  half  that  found,  and  the  value  of 
the  protein  and  carbohydrates  would  be  a  quarter  more. 
Woll  obtained  certain  pound  prices  with  a  list  of  common 


284  THE  FEEDING  OF  ANIMALS 

feeds,  but  Hills  showed  again  that  if  Woll  had  left  out 
rye  bran  these  prices  would  be  greatly  changed.  It 
appears  that  varying  individual  judgments  as  to  the  list 
of  feeds  which  shall  determine  values  may  cause  absurd 
differences  in  the  calculated  market  cost  of  the  nutrients, 
and  introducing  into  the  list  or  withdrawing  from  it  a 
comparatively  unimportant  feeding-stuff  may  lower  or 
raise  the  price  of  one  nutrient  even  one-half. 

A  still  more  serious  difficulty  arises  from  the  fact 
that  often  when  an  apparently  typical  and  proper  list 
of  feeds  is  used  from  which  to  calculate  prices,  the 
use  of  the  method  of  least  squares  results  in  giving  a 
negative  value  to  one  of  the  nutrients.  In  several  cases 
of  this  kind  the  fat  was  shown  to  be  worth  less  than 
nothing,  a  most  absurd  conclusion.  This  mathematical 
method  is,  therefore,  not  available  for  the  valuation 
of  feeding-stuffs,  and  so  far  no  mathematician  has  offered 
one  that  is. 

380.  Physiological  values. — We  are  left  now  to  inquire 
whether  we  may  not  use  physiological  values,  in  other 
words  the  work  which  a  nutrient  will  perform  in  the  ani- 
mal body,  as  a  starting-point  from  which  to  calculate 
relative  values.  If,  for  instance,  it  could  be  demon- 
strated that  protein  has  a  fixed  physiological  value  twice, 
and  fats  three  times,  that  of  carbohydrates,  it  would 
then  be  a  very  simple  matter  to  ascertain  what  propor- 
tion of  the  cost  of  a  ton  of  cottonseed  meal  should  be 
applied  to  each  class  of  nutrients.  To  illustrate,  a  ton  of 
high-grade  cottonseed  meal  contains  about  590  pounds 
of  carbohydrates,  860  pounds  of  protein,  and  260  pounds 
of  fat.  If  these  ingredients  are  assumed  to  have  a  ratio 
of  value  of  1,  2,  and  3,  then  the  whole  would  be  equiva- 
lent to  3,090  units  of  carbohydrates,  the  cost  of  one  unit 


VALUATION   OF   FEEDING-STUFFS  285 

of  which  would  be  about  one  cent,  when  we  pay  $30  a 
ton  for  the  cottonseed  meal.  On  this  basis  it  would  be 
necessary  to  assign  to  the  protein  a  cost  of  two  cents  per 
pound,  and  to  the  fats  three  cents.  If  our  premise  were 
correct  we  could  calculate  the  cost  of  the  nutrients  in  any 
one  of  the  feeding-stuffs,  and  could  either  ascertain  which 
was  the  cheapest  source  of  each  ingredient,  or  by  aver- 
aging could  establish  a  basis  for  a  general  valuation. 
Unfortunately  no  such  a  premise  can  be  correctly  formu- 
lated. We  are  not  yet  wise  enough  to  establish  fixed 
relative  physiological  values  for  the  three  classes  of 
nutrients. 

381.  Energy  values  as  a  basis  of  valuation. — It  may 
be  stated  that  the  energy  values  of  a  unit  of  each  of  the 
nutrients,  protein,  starch,  and  fat  have  been  found  with 
apparent  accuracy.  Why,  then,  may  we  not  establish 
the  relative  value  of  the  nutrients  on  the  basis  of  their 
potential  energy,  which  is  measured  by  the  heat  they  pro- 
duce upon  combustion?  Simply  because  foods  have 
another  function  beside  furnishing  motive  power  to  the 
animal  and  keeping  him  warm.  They  act  as  building- 
material.  The  protein  and  fat  of  milk  and  of  the  body 
tissues  are  derived  from  the  food  compounds,  and  the 
actual  relative  money  value  of  these  compounds  for  con- 
structive purposes  is  not  yet  known.  No  one  has  yet  suc- 
ceeded in  actually  determining  the  relative  money  value 
of  protein,  carbohydrates,  and  vegetable  fats  as  fat  pro- 
ducers, and  we  have  no  data  that  allow  a  definite  conclu- 
sion concerning  the  comparative  money  worth  of  the 
muscle-forming  function  of  protein  as  against  the  fat- 
forming  function  or  energy  function  of  starch.  There  is 
no  promising  prospect,  at  present,  of  being  able  to  com- 
pare foods  on  the  basis  of  their  physiological  importance 


286  THE   FEEDING  OF   ANIMALS 

as  a  means  of  determining  what  should  be  the  relative 
market  cost. 

382.  Conditions  involved  in  the  selection  of  feeding- 
stuffs. — Much    useful    knowledge    is    available    to    the 
stock-feeder  as  a  means  of  guiding  him  to  an  economical 
selection.    Some  of  the  important  facts  to  keep  in  mind 
are:  Some  feeds  carry  more  nitrogenous  matter  than 
others;    some   feeds    are   largely   carbohydrates;    cereal 
grains  contribute  to  the  ration  much  the  same  compounds 
in  much  the  same  proportions;  the  variations  of  composi- 
tion among  the  waste  products  that  are  in  the  market  as 
commercial  feeds;  how  the  coarse  food's  differ  among 
themselves  and  from  the  grains;  some  feeds  are  better 
adapted  than  others  to  a  certain  class  of  animals,  even 
though  of  essentially  the  same  composition,  and  what 
practice  and  science  have  taught  concerning  the  mixtures 
necessary  to  secure  an  efficient  combination  of  nutrients 
for  the  work  to  be  done. 

383.  Digestibility  as  a   basis  for   selecting  feeding- 
stuffs. — After  all  this  is  understood,  there  may  be  several 
feeds   which   are   essentially   alike   in   composition   and 
nutritive  function  but  which  have  different  prices,  and 
there  still  remains  the  problem  of  selecting  the  most 
economical.   It  is  clear  that  the  best  a  feeder  can  do  is  to 
select  the  feeds  that  supply  the  largest  quantity  of  avail- 
able nutrients  for  the  least  money  with  due  reference  to 
the  class  of  nutrients  desired.    If  all  the  feeding-stuffs 
were  digested  in  equal  proportions,  there  would  be  no 
need  of  considering  digestibility,  but  this  is  not  the  case. 
Large  differences  in  digestibility  exist.    From  86  to  88 
per  cent  of  the  dry  matter  of  the  cereal  grains,  oats 
excepted,  is  digested,  while  the  digestibility  of  wheat 
bran,  brewers'  grains,  and  oats  is  on  the  average  only 


VALUATION  OF  FEEDING-STUFFS  287 

about  62  per  cent.  Oats  are  nearly  one-fourth  less  digesti- 
ble than  corn,  barley,  or  rye.  The  refuse  products  known 
as  the  oil  meals  are  less  digestible  than  the  gluten  feeds 
and  meals,  due,  doubtless,  to  the  hulls  contained  in  the 
former.  These  facts  are  important  and  affect  the  nutri- 
tive value  of  commercial  feeds  very  materially. 

384.  Values  based  on  digestibility. — Farmers  should 
base  their  judgment  of  the  value  of  feeding-stuffs  pri- 
marily upon  the  proportions  of  digestible  dry  matter  which 
they  contain.    This  method  will  probably  allow  as  close 
an  approximation  to  relative  values  as  any  which  it  is 
feasible  for  the  farmers  to  use  now  in  practice.    Doubt- 
less "production"  values  (see  Par.  263)  will  ultimately 
offer  a  closer  comparison.    It  is  certainly  more  accurate 
than  a  comparison  of  the  proportions  of  total  dry  matter. 
A  hundred  pounds  of  corn  contains  even  less  dry  matter 
than  the  same  weight  of  oats,  but  the  digestible  material  of 
the  former  is  over  20  per  cent  in  excess  of  that  in  the  latter. 
It  is  to  be  remembered,  however,  that  comparisons  of 
this  kind  can  be  instituted  only  between  feeding-stuffs  of 
the  same  class.   The  relative  values  of  oil  meal  and  corn 
meal  cannot  be  ascertained  in  this  way,  neither  should 
the  relative  values  of  coarse  feeds  and  the  grains  be  so 
compared.    We  should  not  pay  for  oil  meal  and  corn 
meal  on  the  basis  of  the  quantities  of  digestible  nutrients 
which  they  furnish,  because  the  nutrients  are  not  identi- 
cal in  the  two  cases.   Digestible  material  which  is  40  per 
cent  protein  cannot  be  measured  by  digestible  material 
which  is  only  10  per  cent  protein. 

385.  Digestibility   of   various   feeds. — The   following 
table  shows  the  digestible  material  in   100  pounds  of 
various  feeding-stuffs,  as  calculated  from  average  com- 
position and  digestibility.   In  the  case  of  hays,  the  water- 


288 


THE  FEEDING  OF  ANIMALS 


content  is  assumed  to  be  uniform,  viz.,  12.5  per  cent, 
while  the  percentages  given  for  the  grains  are  the  averages 
found  by  analysis: 

TABLE  LXI 


Per  cent  of 

digestibility 

of  dry 

matter 


Pounds  of 
dry  matter  in 

100  of  the 
feeding-stuff 


Pounds 
digestible 
dry  matter 

in  100  of 
feeding-stuff 


Class  I — Dried  grass  plants 

Corn  fodder,  fresh,  average       .  69 

Corn  stover ' :  57 

Hungarian  hay    .    ..  .    .    .  'V  £;  65 

Oat  straw 54 

Orchard  grass  hay      56 

Red-top  hay 60 

Timothy,  all 55 

Timothy,  in  bloom  or  before     .  59 

Timothy,  after  bloom     ....  52 

CZass  // — Dried  legumes 

Alfalfa      :  .  62 

Clover,  alsike      -.,./•"  59 

Clover,  red      .....  \  ..  ~.\  58 

Clover,  white       ...,;...,  66 

Class  III — Cereal  grains 

Barley      .  ,.   . 86 

Corn  meal .   .  v  88 

Corn-and-cob  meal     ...   '-.   .  79 

Oats    -•;;  .  .  70 

Oat  feed,  mainly  hulls    ....  34 

Rj^e  meal     ...'.,"._„....  87 

Class  IV — Nitrogenous  feeds 
16-30  per  cent  protein. 

Brewers'  grain 62 

Distillers'  grains  (from  rye) — 

Gluten  feed      87 

Maltsprouts 67 

Wheat  bran 62 

Wheat  middlings 75 

Pea  meal  87 


20 
60* 

87.5 
90 

87.5 
87.5 
87.5 
87.5 
87.5 


87.5 

87.5 
87.5 
87.5 


89 
85 
85 
89 
92 
88 


92 

92 
90 


90 


13.8 

34.2 

56.9 

48.6 

49 

52.5 

48.1 

51.6 

45.5 


54.2 
51.6 
50.7 
57.7 


76.5 
74.8 
67.1 
62.3 
30.3 
76.5 


57 

80 
60.3 
54.5 
66 

78.3 


*Assumed. 


VALUATION   OF  FEEDING-STUFFS 


289 


TABLE  LXI,  CONTINUED 


Per  cent  of 
digestibility 
of  dry 
matter 

Pounds  of 
dry  matter  in 
100  of  the 
feeding-  stuff 

Pounds 
digestible 
dry  matter 
in  100  of 
feeding-  stuff 

Class  V  —  Nitrogenous  feeds 

30-45  per  cent  protein 

Distillers'  grains  (from  corn)  — 

Gluten  meal     

87 

92 

80 

Linseed  meal,  old  process 

79 

91 

71.9 

Linseed  meal,  new  process    . 

78 

90 

70.2 

Cottonseed  meal,  high  grade 

90 

92 

82.8 

Cottonseed  meal,  low  grade 

65 

92 

59.8 

It  is  fully  recognized  that  these  figures  cannot  be 
taken  as  absolute  relative  values.  Feeding-stuffs,  bear- 
ing the  same  name,  are  not  always  exactly  similar  in 
composition  or  in  equally  good  condition.  Variations 
in  the  moisture-content  occur,  especially  with  the  coarse 
fodders.  Even  after  allowing  for  all  these  factors,  results 
will  not  follow  exactly  the  quantities  of  digestible  matter 
supplied,  because  there  seems  to  be  a  greater  adapta- 
bility of  some  feeds  to  the  needs  of  a  particular  species. 
Nevertheless  we  are  forced  to  conclude  that  food  mate- 
rials of  the  same  class  must  furnish  energy  and  building- 
material  closely  in  proportion  to  what  is  digested  from 
them. 

386.  Valuations  based  on  protein-content.— Certain 
writers  and  speakers  base  the  value  of  nitrogenous  feed- 
ing-stuffs, from  bran  up,  entirely  on  the  protein-content, 
and  they  divide  the  price  by  the  pounds  of  protein  in  a 
ton  in  order  to  determine  the  relative  economy  of  pur- 
chasing this  or  that  material,  and  the  feeding-stuff  in 
which  the  protein  cost  is  the  least  when  so  reckoned  is 

3 


290  THE  FEEDING  OF  ANIMALS 

regarded  as  the  economical  one  to  purchase.  This  method 
seems  to  be  absurd,  for  it  is  an  assumption  that  the 
nutritive  value  of  the  carbohydrates  and  fat  in  commer- 
cial foods  may  be  ignored.  The  argument  is  that  the 
farm  furnishes  carbohydrates  in  abundance,  and  that 
commercial  products  should  merely  serve  the  purpose  of 
reinforcing  the  protein-supply.  If  the  carbohydrates  of 
the  farm  have  no  selling  value  then  this  argument  has 
some  force,  but  this  is  ordinarily  not  the  case.  When 
starch  and  similar  compounds  must  be  purchased  as  a 
necessary  accompaniment  of  protein,  thus  causing  a  sur- 
plus of  carbohydrate  food,  certainly  hay,  oats,  corn, 
barley,  or  some  other  home  product  may  be  sold  to 
relieve  this  surplus. 

387.  Feed  values  based  on  feeding  experiments. — 
Many  practical  feeding  experiments  have  been  •  con- 
ducted for  the  purpose  of  comparing  the  different  grain 
products  as  foods  for  the  various  classes  of  animals.  Useful 
facts  have  been  reached  in  this  way,  especially  as  to  the 
greater  adaptability  of  some  materials  than  others  for  a 
particular  species.  But  experiments  of  this  kind  cannot 
be  relied  upon  to  fix  relative  values  of  feeding-stuffs  for 
milk  production,  beef  production,  or  for  any  other  pur- 
pose. This  is  so,  first  of  all,  because  the  errors  of  such 
tests  are  so  large  that  we  cannot  regard  their  apparent 
outcome  as  establishing  constants.  Again,  the  problems 
involved  are  too  complex  and  the  effect  of  a  given  ration 
too  dependent  upon  variable  conditions,  to  allow  logical 
conclusions  from  such  experimental  data.  The  difficul- 
ties of  the  situation  will  be  made  clear  to  anyone  by  a 
careful  study  of  the  whole  mass  of  data  resulting  from 
feeding  tests.  Differences  appear,  some  of  which  are  con- 
sistently in  one  direction,  especially  in  comparing  nitrog- 


VALUATION  OF  FEEDING-STUFFS  291 

enous  with  carbohydrate  foods,  but  as  between  mate- 
rials of  the  same  class  their  comparative  values  as  indicated 
by  different  experiments  are  greatly  variable,  even  con- 
tradictory. Any  one  who  endeavors  to  reach  fixed  and 
universal  valuations  on  an  experimental  basis  of  this 
kind  will  find  himself  involved  in  hopeless  confusion. 

388.  The  verdict  of  the  cow. — Once  in  a  while  some 
one  talks  wildly  about  leaving  food  valuation  to  the 
"old  cow."  It  is  sometimes  considered  a  telling  argument 
against  the  chemist's  wisdom  to  declare  that  he  and  the 
old  cow  do  not  agree.  Certainly  the  cow  knows  better 
than  the  chemist  what  she  likes  to  eat,  and  it  is  little  use 
to  offer  her  foods  she  does  not  relish.  Even  a  chemist 
knows  that.  If,  however,  a  dozen  commercial  feeding- 
stuffs  were  spread  around  on  a  barn  floor  it  would  be 
much  safer  to  trust  an  agricultural  chemist,  especially 
one  experienced  in  stock-feeding,  to  select  a  ration  than 
any  cow  ever  grown — Holstein,  Ayrshire,  Jersey,  long- 
horned,  dishorned,  or  what  not.  The  cow  would  probably 
get  at  the  corn  meal  and  stay  with  it  until  well  on  the 
way  to  a  fatal  case  of  indigestion.  Her  judgment  is  just 
about  as  good  as  that  of  a  child  with  a  highly  cultivated 
"sweet  tooth." 


CHAPTER  XVII 

THE  SELECTION  AND  COMPOUNDING  OF 
RATIONS 

THERE  are  several  factors  that  must  be  considered 
in  selecting  an  efficient  and  economical  ration — factors 
which  relate  to  both  science  and  practice.  It  is  gener- 
ally desirable  that  a  food  mixture  shall  be  "balanced," 
but  this  gives  no  assurance  that  a  ration  can  be  fed 
under  particular  conditions  with  satisfactory  results. 
Intelligent  observation  in  the  barn  or  stable  really  takes 
the  first  place  in  formulating  a  method  of  feeding,  which 
is  supplemented  to  a  valuable  extent  by  the  scientific 
insight  of  the  chemist  and  physiologist.  A  ration  may  be 
chemically  right  and  practically  wrong,  but,  at  the  same 
time,  it  is  worth  much  to  the  feeder  to  be  assured  that  the 
nutrients  which  he  supplies  to  his  animals  will  meet  their 
physiological  needs.  Moreover,  commercial  relations 
such  as  the  prices  of  feeds  and  product  must  be  con- 
sidered, and  this  is  a  business  question  and  not  a  scien- 
tific matter. 

389.  Palatableness  as  a  factor  in  feeding  animals. — 
A  successful  ration  must  be  palatable.  An  agreeable 
flavor  is  not  a  source  of  energy  or  of  building-material, 
but  it  tends  to  stimulate  the  digestive  and  assimilative 
functions  of  the  animal  to  their  highest  efficiency,  and  is 
a  requisite  for  the  consumption  of  the  necessary  quantity 
of  food.  Common  experience  teaches  that  when  cows  or 
animals  of  any  other  class  do  not  like  their  food,  they 

(292) 


SELECTION   OF  RATIONS  293 

"do  not  do  well."  Persons  sometimes  claim  that  they 
have  contracted  dyspepsia  by  eating  food  which  is  not 
relished,  even  food  that  is  nutritious  and  well  cooked, 
and  which  would  be  entirely  satisfactory  to  other  indi- 
viduals. The  situation  is  still  worse  when  the  food  is 
undesirable  both  as  to  texture  and  flavor.  We  have 
reason  to  believe  that  animals  are  susceptible  to  the  same 
influences  as  man,  though  perhaps  not  to  the  same 
extent.  An  animal  is  more  than  a  machine,  and  is  pos- 
sessed of  a  nervous  organism,  the  existence  of  which 
should  never  be  ignored. 

One  way  of  stimulating  an  animal's  appetite  is  to 
feed  a  variety  of  materials.  Continuous  feeding  on  a 
single  coarse  food  and  one  grain  is  not  conducive  to  the 
best  results.  The  various  available  fodders  and  grains 
should  be  so  combined  as  to  allow  the  feeding  of  all  of 
them  throughout  the  season,  and  avoid  the  exclusive  use 
of  one  or  two  kinds  for  any  extended  period  of  time.  The 
skilful  feeder,  then,  will  not  fail  to  make  the  ration  as 
palatable  as  possible,  and  will  always  consider  the  idiosyn- 
crasies of  appetite  of  each  animal. 

390.  Adaptation  of  rations. — The  ration  must  be 
adapted  to  the  species.  This  is  obvious  as  relates  to 
quantity,  but  is  equally  true  of  the  kinds  of  materials. 
For  instance,  both  poultry  and  swine  generally  eat  cot- 
tonseed meal  with  reluctance  and  with  danger  to  health. 
Wheat  bran  is  less  desirable  for  swine  than  for  other 
species.  The  horse  and  the  hog  are  not  adapted  to  rough 
fodder  as  are  the  ruminants.  It  is  useless,  however,  to 
mention  at  this  point  other  instances  of  this  character, 
or  to  comment  on  their  importance,  further  than  to 
emphasize  the  foolishness  of  trying  to  bring  all  species  of 
animals  to  a  common  basis  in  the  supply  of  feeding-stuffs. 


294  THE  FEEDING  OF   ANIMALS 

391.  Physiological    requirements. — The    physiological 
requirements    of    the    animal    must    be    considered.     A 
ration  of  maximum  physiological  efficiency  and  economy 
must  contain  the  several  nutrients  in  such  quantities  and 
proportions   as  will  meet  the  needs  of  the  particular 
animal  fed,  without  waste.  This  statement  is  based  upon 
facts   given   elsewhere   in  this  volume   relative   to   the 
demands  of  the  animal  body  and  the  functions  of  the 
nutrients. 

It  remains  now  for  us  to  consider  how  to  compound  * 
such  rations  as  are  desired,  or  those  that  are  adapted 
in  kind  and  quantity  to  the  requirements  which  they 
are  to  meet.  Obviously,  the  first  essential  for  doing 
this  is  the  adoption  of  standards  to  which  rations  should 
conform,  for  if  we  do  not  have  these  there  is  no  possi- 
bility of  concluding  whether  one  food  mixture  is  better 
or  worse  than  another  for  a  particular  purpose. 

392.  Feeding  standards. — Such  standards  have  been 
proposed,  which  we  knew  first  as  German  feeding  stand- 
ards.    The   standards  that  are  now  accepted   are  the 
result  of  numerous  and  elaborate  studies  of  the  balance 
of  loss  or  gain  to  the  animal  organism  when  rations  of 
various  kinds  were  fed  to  animals  at  rest,  at  work,  and 
when  producing  meat,  wool,  or  milk,  in  desirable  quan- 
tities.    They  relate  entirely  to  physiological   demands 
without  reference  to  the  cost  of  the  rations  or  to  the 
profits  which  may  result  from  then*  use. 

The  earlier  standards  were  developed  chiefly  in  Ger- 
many but  those  now  most  in  favor  are  based  upon  Ameri- 
can experimental  data. 

These  standards  are  variable  in  two  main  factors: 
(1)  The  quantity  of  available  nutrients,  and  (2)  the 
relative  proportions  of  the  classes  of  nutrients.  Quan- 


SELECTION   OF  RATIONS  295 

tity  is  an  essential  consideration,  for  it  is  obvious  that 
enough  energy  and  building-material  must  be  supplied 
to  do  a  given  work.  It  is  also  obvious  that  quantity  must 
be  a  variable  factor  according  as  the  animal  is  large  or 
small,  doing  hard  or  light  work,  giving  much  or  little 
milk,  or  fattening  rapidly  or  slowly. 

Account  must  be  made  of  the  proportions  of  the 
nutrients,  because  protein,  for  instance,  has  peculiar 
functions  which  other  nutrients  cannot  exercise,  and 
less  than  a  certain  minimum  of  the  proteins  in  any  given 
case,  would  limit  production  by  just  the  amount  of  the 
deficiency.  In  order  for  the  protein  to  serve  its  maxi- 
mum usefulness,  its  energy  should  not  be  encroached 
upon  to  fill  a  place  equally  well  or  better  taken  by  carbo- 
hydrates; consequently,  the  proportion  of  carbohydrates 
must  also  be  considered. 

393.  Nutritive  ratio. — The  relative  proportion  of  the 
nutrients  of  a  ration  is  known  as  the  nutritive  ratio.  By 
this  term  is  meant  the  relation  in  quantity  of  the  digesti- 
ble protein  to  all  the  other  digestible  organic  matter 
reckoned  in  terms  of  carbohydrates.  If  we  multiply  the 
quantity  of  fat  by  2.25  we  get  its  carbohydrate  equivalent, 
and  if  we  add  this  product  to  the  quantity  of  diges- 
tible carbohydrates  present  we  have  the  carbohydrate 
value  of  the  digestible  matter  other  than  the  protein. 
This  sum  divided  by  the  number  representing  the  pro- 
tein gives  the  nutritive  ratio.  For  instance,  in  a  ration 
mentioned  later  there  are  .94  pound  protein,  9.65  pounds 
carbohydrates,  and  .49  pound  fat.  (.49X2.25 +9.65) -H 
.94=11.4.  1: 11.4  is  therefore  the  nutritive  ratio  of  the 
ration. 

A  nutritive  ratio  may  be  designated  as  "narrow," 
"wide,"  or  "medium."  These  terms  do  not  represent 


296 


THE  FEEDING  OF  ANIMALS 


exact  limits  to  which  there  is  universal  agreement.  A 
narrow  ratio  is  one  where  the  proportion  of  protein  is 
relatively  large,  not  less  perhaps  than  1 : 5.5.  A  wide 
ratio  is  one  where  the  carbohydrates  are  very  greatly 
predominant,  or  in  larger  proportion  perhaps  than  1:8. 
Anything  between  1 : 5.5  and  1 : 8  may  properly  be 
spoken  of  as  a  medium  ratio. 

Merely  for  the  purpose  of  illustration,  three  feeding 
standards  are  given  in  this  connection.  These  are  selected 
from  standards  proposed  by  Wolff,  as  modified  by  Leh- 
mann.  They  refer  in  all  instances  to  animals  weighing 
1,000  pounds: 

TABLE  LXII.    FOR  1,000  POUNDS  LIVE  WEIGHT  DAILY 


Dry 

sub- 

Diges- 
tible 

Diges- 
tible 
car- 

Diges- 
tible 

Total 
diges- 
tible 

Nutri- 
tive 

stance 

bohy- 

fat 

organic 

ratio 

drates 

matter 

Pounds 

Pounds 

Pounds 

Pounds 

Pounds 

Cow,  yield  milk,  22  Ibs.  . 

29 

2.5 

13 

.5 

16 

1:5.7 

Fattening  steer,  1st  per. 

30 

2.5 

15 

.5 

18 

1:6.5 

Horse,  medium  work  .    . 

24 

2 

11 

.6 

13.6 

1:6.2 

These  and  other  standards  will  be  discussed  later 
when  we  come  to  consider  the  feeding  of  the  various 
farm  animals.  Our  present  purpose  is  simply  to  make 
clear  the  steps  necessary  to  bringing  the  quantity  and 
composition  of  the  ration  into  conformity  with  the 
standard  selected. 

394.  Calculating  a  ration. — As  a  means  of  showing 
the  steps  involved  in  calculating  what  a  ration  is,  and 
how  to  improve  it  if  necessary,  we  will  assume  that  it  is 
desired  to  learn  whether  a  food  mixture  which  a  milch 
cow  is  eating  is  what  it  should  be,  and  if  it  is  not,  how  to 


SELECTION  OF  RATIONS  297 

make  it  so.  The  standard  ration  for  a  1,000-pound  cow, 
giving  twenty-two  pounds  of  average  milk,  expressed  in 
terms  of  water-free  nutrients,  has  been  given  in  the 
preceding  table. 

The  first  point  which  requires  our  attention  is  that 
this  standard  is  mainly  expressed  in  terms  of  water-free 
digestible  nutrients.  This  means  that  we  must  take 
into  account  the  composition  and  digestibility  of  the 
particular  feeding-stuffs  which  enter  into  a  ration,  if  we 
would  discover  what  it  really  is  supplying  of  available 
food  compounds.  It  is  evident  that  usually  feeders  can- 
not have  their  cattle  foods  analyzed,  and  so  they  must 
resort  to  the  tables  of  composition  and  digestibility, 
which  are,  or  may  be,  in  the  hands  of  every  farmer. 

395.  Calculation  of  digestible  nutrients. — Feeding- 
stuffs,  especially  fodders,  differ  within  quite  wide  limits 
in  what  they  contain  and  in  what  the  animal  will  dissolve 
from  them,  according  to  the  species,  stage  of  growth  and 
conditions  of  curing,  and  an  average  percentage  of  pro- 
tein or  an  average  coefficient  of  digestibility  is  likely  to 
differ  widely  from  the  actual  facts  as  pertaining  to  a 
particular  material.  All  that  can  be  done  is  to  select  as 
nearly  as  possible  the  figures  which  have  been  found  for 
feeding-stuffs  in  the  condition  of  those  which  are  to  be 
fed.  If  the  hay  is  from  mature  grass,  use  the  composi- 
tion percentages  and  digestion  coefficients  given  for 
such  hay;  if  the  silage  is  from  mature  corn,  pursue  a 
similar  course  in  this  case,  and  so  on.  Difficulty  may  be 
met  in  finding  suitable  figures,  because  tables  of  com- 
position and  digestibility  are  not  fully  developed  and 
classified  on  the  basis  of  the  character  of  the  materials. 

The  assumed  ration  which  we  wish  to  discuss  con- 
sists of: 


298 


THE  FEEDING  OF  ANIMALS 


Pounds 

Late-cut  timothy  hay     .    10 
Corn  silage 25 


Hominy  chops     . 
Winter-wheat  bran 


Pounds 
.    2 
.    3 


The  averages  for  composition  and  digestibility,  which 
are  as  likely  as  any  to  represent  these  and  other  mate- 
rials, are  the  following: 


TABLE  LXIII 


Composition 

Digestibility 

• 

i 

1 

a 

1 

Nitrogen- 
free  extract 

g 

Protein 

i 

£ 

Nitrogen- 
free  extract 

1 

Per 
cent 
51 
56 
82 
92 
63 

93 

Timothy  hay,  late 
cut    
Clover  hay      .    . 
Corn  silage     .    . 
Hominy  feed  .    . 
Wheat  bran     .    . 
Linseed  meal,  new 
process     .    .    . 

Per 
cent 
14 
15 
80 
11 
10 

9 

Per 
cent 
3.9 
7.7 
1.1 
2.5 
6.2 

5.6 

Per 
cent 
5.2 
13.3 
1.7 
10.4 
16.1 

37.4 

Per 
cent 
29.7 
24.3 
5.4 
4.2 
10. 

8.9 

Per 
cent 
45.2 
37.2 
11.1 
63.9 
53.3 

36.4 

Per 
cent 
2. 
2.5 
.7 
8. 
4.4 

2.7 

Per 
cent 
43 
58 
51 
65 
77 

85 

Per 
cent 
46 
54 
65 
67 
39 

74 

Per 
cent 
59 
65 
71 
89 
71 

84 

The  first  step  in  the  calculation  is  to  find  out  what 
percentages  of  digestible  material  the  components  of  our 
proposed  ration  contain,  and  we  shall  obtain  these  by 
multiplying  the  percentages  of  composition  by  the  co- 
efficients of  digestibility  and  dividing  the  product  by 
100;  that  is,  if  timothy  hay  contains  5  per  cent  of  pro- 
tein, 45  per  cent  of  which  is  digestible,  then  .45  of  5  will 
be  the  percentage  of  digestible  protein  in  the  hay.  In 
this  way  the  following  figures  were  obtained.  The  per- 
centage of  digestible  carbohydrates  represents  the  sum 
of  the  quantities  digested  from  both  the  crude  fiber  and 
the  nitrogen-free  extract.  Tables  are  now  published 
which  show  percentages  of  digestible  ingredients,  and 
which  will  render  this  calculation  largely  unnecessary: 


SELECTION  OF  RATIONS 


299 


TABLE  LXIV 


Digest- 
ible 
protein 

Digest- 
ible 
carbo- 
hydrates 

Digest- 
ible 
fats 

Total 
digest- 
ible 
organic 
nutrients 

Timothy  hay      .    .    ,    .    .  «  .  '  . 

Per  cent 

2.2 

Per  cent 

40.4 

Per  cent 
1 

Per  cent 
43  6 

Clover  hay  .    .        .    .  '      '.    .-   .    ,  • 

7.7 

373 

1  4 

464 

Corn  silage      .    .    .v,    .-..•.    ,*.' 
Hominy  feed       •  .    . 
Wheat  bran    ..    ^    ..... 

.9 
6.8 
12.4 

11.4 

58.7 
41.7 

.6 
7.4 

28 

12.9 
72.9 
569 

Linseed  meal      i  •    • 

31. 

37.1 

2.5 

70.6 

396.  Digestible  nutrients  in  a  given  ration. — The 
second  step  is  to  calculate  the  pounds  of  digestible  nu- 
trients in  the  quantities  of  the  several  feeding-stuffs  to 
be  used.  It  is  clear,  for  instance,  that  10  pounds  of  hay 
will  contain  .10  of  the  amounts  in  100  pounds,  so  we 
simply  need  to  multiply  the  percentage  of  digestible 
protein  and  so  on  by  10  and  divide  by  100  in  order  to 
learn  what  10  pounds  of  hay  will  furnish  to  the  animal. 
If  we  make  this  computation  for  each  constituent  of  each 
feeding-stuff,  we  reach  the  figures  of  the  following  table: 

TABLE  LXV 


Digestible 
protein 

Digestible 
carbo- 
hydrates 

Digestible 
fat 

Total 
digestible 
organic 
matter 

Nutritive 
ratio 

Timothy  hay,  10  Ibs.    . 
Corn  silage,  25  Ibs.    .    . 
Hominy  feed,  2  Ibs.  .    . 
Wheat  bran,  3  Ibs.    .    . 

Pounds 

.22 
.22 
.14 
.37 

Pounds 

4.04 
3.85 
1.17 
1.25 

Pounds 

.10 
.12 
.15 

.08 

Pounds 

4.36 
4.19 
1.46 
1.70 

.95 

10.31 

.45 

11.08 

1:12 

Several  authors  have  published  tables  showing  the 
proportions  of  digestible  nutrients  in  feeding-stuffs. 


300 


THE  FEEDING  OF  ANIMALS 


397.  Correcting  an  insufficient  ration. — When  we  come 
to  compare  this  ration  with  the  standard  ration  we  find 
it  is  seriously  defective  in  two  particulars:  it  contains 
far  too  little  digestible  organic  matter  and  the  nutri- 
tive ratio  is  too  wide. 

In  order  to  correct  these  faults,  we  must  add  digesti- 
ble organic  matter  which  contains  a  much  larger  pro- 
portion of  protein  than  is  found  in  any  of  the  materials 
so  far  selected,  and  we  must  seek  such  a  supply,  in  part 
at  least,  among  the  highly  nitrogenous  feeding-stuffs  like 
the  oil  meals  and  gluten  meals.  It  is  easy  for  one  with 
experience  to  see,  also,  that  all  the  necessary  additional 
organic  matter  cannot  be  secured  from  a  highly  nitroge- 
nous food  without  increasing  the  protein  supply  unneces- 
sarily. In  order  to  avoid  this,  the  amount  of  silage  may 
be  raised  ten  pounds  and  still  not  feed  an  excessive  quan- 
tity. If  clover  hay  is  available,  it  would  also  be  well  to 
substitute  five  pounds  of  it  for  five  pounds  of  the  timo- 
thy. If,  then,  we  add  to  the  ration  three  pounds  of  lin- 
seed meal  we  shall  approximate  more  nearly  to  our 
standard. 

TABLE  LXVI 


Total 

*    '.' 

Car- 

digest- 

Nutri- 

Protein 

bohy- 

Fat 

ible 

tive 

drates 

organic 

ratio 

matter 

Timothy  hay,  5  pounds      .    .    . 

.11 

2.62 

.05 

2.18 

Clover  hay,  5  pounds     .... 

.37 

1.86 

.07 

2.30 

Corn  silage,  35  pounds   .... 

.31 

3.99 

.21 

4.51 

Hominy  feed,  2  pounds  .... 

.13 

1.17 

.15 

1.45 

Wheat  bran,  3  pounds    ......  \| 

.37 

1.25 

.08 

1.70 

Linseed  meal,  3  pounds      .    .    . 

.93 

1.11 

.07 

2.11 

2.22 

11.40 

.63 

14.25 

1:6.8 

SELECTION   OF  RATIONS  301 

This  ration  is  still  below  the  standard  in  quantity, 
but  as  the  relation  of  the  nutrients  is  approximately 
what  is  called  for,  it  is  only  necessary  to  increase  the 
quantities  of  each  component  about  one-fifteenth  in 
order  to  furnish  the  animal  sixteen  pounds  of  digestible 
organic  matter.  It  is,  however,  a  good  ration  for  cows 
of  the  smaller  breeds  weighing  from  800  to  900  pounds. 

398.  Relation  of  ration  to  size  of  animal. — There  are 
several  points  to  be  considered  in  this  connection.  First 
of  all,  the  standard  rations  are  the  quantities  to  be  fed 
a  day  and  for  1,000  pounds  live  weight.  This  is  ordi- 
narily taken  to  mean  that  if  a  1,000-pound  cow  requires 
16  pounds  of  digestible  nutrients,  an  800-pound  cow  should 
be  supplied  with  only  four-fifths  as  much,  or  12.8  pounds, 
or  that  a  1,200-pound  horse  needs  50  per  cent  more  food 
than  one  weighing  800  pounds.  Unfortunately  this  sim- 
ple mathematical  way  of  calculating  rations  does  not  meet 
the  plain  requirements  of  practice.  The  needs  of  a  pro- 
ducing or  working  animal  are  not  directly  proportional 
to  its  size,  for  the  work  done  or  the  quantity  of  pro- 
duction is  the  dominating  factor.  It  is  certain  that  feeding 
milch  cows  or  working  horses  in  proportion  to  weight 
alone  contravenes  known  facts. 

However,  we  cannot  ignore  the  size  of  the  animal 
in  determining  the  quantity  of  the  ration.  Concerning 
this,  Armsby  says:  "The  function  of  the  maintenance 
ration  is  essentially  to  supply  heat  to  the  body  to  replace 
the  constant  loss  that  takes  place.  Now,  Henneberg 
has  long  ago  shown  that,  in  round  numbers,  over  90  per 
cent  of  this  heat  is  removed  by  radiation  and  evapora- 
tion. Consequently,  we  should  expect  the  demands  of 
the  organism  for  heat  (i.  e.,  for  maintenance),  to  be  pro- 
portional to  its  surface  (including  lung  surface),  rather 


302  THE  FEEDING  OF  ANIMALS 

than  to  its  weight,  and  the  more  recent  researches  of 
Rubner  have  confirmed  this  theoretical  conclusion." 
For  the  purposes  of  calculation,  it  is  assumed  that  ani- 
mals are  geometrically  similar  figures  and  therefore  that 
then*  surfaces  are  proportional  to  the  cube  root  of  the 
square  of  their  weights.  Several  steers  having  weights 
from  1,000  up  to  1,700  pounds  would  need,  on  this  basis, 
amounts  of  digestible  food  for  maintenance  propor- 
tional to  figures  given  in  the  table  below: 

Weight  of  the  animal  Proportion  of  food  per  1,000 

approximately  pounds  live  weight 

1,000  pounds 100 

1,100  pounds  ..*•....'. 96 

1,200  pounds  .    .    .  •'.•vi 93 

1,300  pounds 90 

1,400  pounds 88 

1,500  pounds 86 

1,600  pounds 84 

1,700  pounds 82 

For  adjusting  a  maintenance  ration  to  the  weight  of  a 
steer  or  horse,  this  method  seems  to  have  a  plausible 
basis,  but  it  is  evidently  less  applicable  to  dairy  cows  or 
rapidly  growing  or  fattening  animals,  for  in  these  cases 
production  and  not  size  must  be  chiefly  considered. 

399.  The  protein-supply. — The  matter  of  the  protein- 
supply  is  important.  If  we  are  trying  to  supply  the  needs 
of  a  cow  giving  twenty-five  pounds  of  milk,  or  of  a  steer 
gaining  two  pounds  of  body  substance  daily,  there  is 
without  question  a  minimum  quantity  of  food  protein 
absolutely  necessary  in  each  case.  These  necessary 
quantities  are  certainly  not  the  same  for  all  individuals, 
but  they  are  not  likely  to  differ  widely  between  single 
animals  of  the  same  class  and  productive  capacity.  It  is 
safe  to  assert  that  the  earlier  protein  standards  are  those 
which  it  is  practicable  to  feed  and  which  unquestionably 


SELECTION  OF  RATIONS  303 

generously  meet  the  demands  of  the  class  of  animals  for 
which  they  are  designed. 

400.  Earlier  protein  standards  revised. — Through  more- 
recent   investigations,    revisions   of   the   earlier   protein 
standards  have  been  recommended.    These  are  in  gen- 
eral in  the  direction  of  a  lower  minimum  of  protein,  and 
the  data  secured  seem  to  justify  the  change.  At  the  same 
time,  care  should  be  taken  in  not  fixing  the  protein  mini- 
mum too  low,  partly  because  a  generous  protein-supply 
promotes  the  general  welfare  of  the  animal,  and  partly 
because  of  the  variable  efficiency  of  the  single  proteins 
which  are  found  in  the  different  feeding-stuffs  in  greatly 
unlike  proportions.   The  amount  of  protein  fed  in  a  given 
case  should  be  such  as  to  guarantee  a  sufficient  amount 
for  the  actual  constructive  work  demanded.  (See  Par.  275.) 
Probably  with  certain  feeding-stuffs  the  minimum  might 
be  lower  than  with  others.    It  is  very  evident  then  that 
the  protein-supply  in  feeding    formulas  for  production 
cannot  safely  be  resolved  to  the  exact  limitation  of  the 
nitrogen  compounds  needed.    The  standards  that  have 
been  suggested  will  be  considered  in  the  following  pages. 

401.  Presence  of  growth-promoting  bodies. — The  dis- 
covery of  growth-promoting  bodies  attached  to  cattle 
foods  (see  Par.  278)  leads  to  the  conclusion  that  rations 
should  be  selected  under  certain  conditions  with  refer- 
ence to  the  presence  of  these  essential  compounds.   This 
is  especially  true  where  animals  are  likely  to  be  fed  on  a 
restricted  diet,   as,   for  instance,   swine,   or  where  by- 
product feeds  are  used  the  treatment  of  which  may  have 
removed  part  or  all  of  the  food  accessories.  With  animals 
eating  the  forage  portion  of  plants  in  large  quantities, 
such  as  the  bovines,  there  is  little  danger  that  there  will 
be  a  deficiency  in  the  food  of  these  essential  compounds. 


304  THE  FEEDING  OF  ANIMALS 

As  these  compounds  exist  in  much  smaller  proportion  in 
grain,  swine  when  confined  to  a  restricted  grain  diet  may 
suffer  from  a  lack  of  such  accessory  bodies.  The  addition, 
therefore,  to  the  grain  food  of  swine  of  some  green  food, 
such  as  alfalfa,  would  appear  to  insure  the  animal  against 
defective  growth. 

Dairy  by-products  are  carriers  of  both  Fat-soluble  A 
and  Water-soluble  B,  and  the  recognized  value  of  these 
by-products  in  pig-feeding  is  perhaps  partly  due  to  the 
presence  of  these  substances.  As  time  proceeds,  the 
knowledge  necessary  to  the  compounding  of  rations  with 
reference  to  the  growth-promoting  value  will  doubtless 
be  greatly  enlarged. 

402.  Influence  of  ration  on  quality  of  product. — The 
rations   should   be   compounded   with   reference  to  the 
quality  of  the  product.    Our  knowledge  of  the  influence 
of  foods  upon  the  quality  of  meat  products  is  by  no  means 
complete,  but  that  food  has  an  influence  upon  the  flavor 
of  milk  and  upon  the  chemical  and  physical  properties  of 
butter,  seems  to  be  fairly  well  established. 

403.  Home  supply  of  feeding-stuffs  to  be  considered. — 
Rations  should  be  compounded  with  reference  to  the 
home   supply   of   feeding-stuffs   and   to   market   prices. 
Economy  often  demands  that  the  materials  in  hand  shall 
be  used  even  if  the  ration  is  not  ideal.    Again,  there 
are  several  protein  foods  which  may  be  used,  and  it  is 
often  only  a  question  of  price  in  determining  which  should 
be  purchased.     Notwithstanding   the   claims  of  manu- 
facturers, there  is  no  one  feeding-stuff  essential  to  the 
health  of  animals  or  to  the  highest  quality  of  the  pro- 
duct, so  that  the  feeder  may  often  consider  the  matter 
of  cost  and  select  the  cheapest  source  of  protein  without 
in  any  way  impairing  the  ration. 


SELECTION  OF  RATIONS  305 

404.  Selection  of  a  ration  largely  a  business  matter. — 
Those  who  have  carefully  followed  the  preceding  state- 
ments must  have  become  convinced  that  the  selection 
of  a  ration  which  shall  be  the  best  possible  from  a  business 
standpoint  is  not  a  simple  matter.  We  must  always  dis- 
tinguish between  the  combination  that  is  most  efficient 
physiologically  or  productively,  and  the  one  that  is  the 
source  of  largest  profit.  It  is  often  the  case — perhaps 
generally — that  a  food  mixture  which  induces  a  high  rate 
of  production  is  the  most  profitable  one  to  use,  but  this 
occurs  only  when  business  conditions  make  it  possible. 
Many  seem  to  think  that  if  a  ration  is  "balanced"  it 
necessarily  meets  all  the  requirements  for  the  maximum 
profit,  but  this  is  an  erroneous  view. 

For  instance,  a  farmer  somewhat  remote  from  the 
markets  may  have  on  hand  an  abundant  supply  of  hay 
and  home-raised  grains  of  such  a  character  that  it  is 
impossible  to  compound  them  so  as  to  conform  to  the 
accepted  feeding  standard  for  milch  cows.  If  the  prices 
of  dairy  products  are  low,  and  those  of  purchased  feed- 
ing-stuffs are  high,  it  is  entirely  possible  for  the  farmer 
to  secure  more  profit  from  his  cows  with  an  "unbalanced" 
ration  than  with  one  which  has  a  more  nearly  correct 
nutritive  ratio. 

The  western  stockman  can  often  afford  to  waste 
corn  on  fattening  steers  rather  than  use  it  with  greater 
physiological  economy  by  mixing  it  with  purchased 
grains.  The  cost  of  the  latter  would  soon  offset  the 
profits  otherwise  possible.  All  this  is  equivalent  to  say- 
ing that  practical  considerations  often  justify  a  wide 
departure  from  the  standard  rations.  Hills  states  the 
case  well  when  he  says: 

"The  study  of  the  requirements  of  the  individual 


306  THE  FEEDING  OF  ANIMALS 

animal  and  the  adapting  of  food  to  its  needs  is  to  be 
preferred  to  placing  the  herd,  as  a  whole,  upon  any 
inflexible  ration.  The  capacity  of  an  animal  to  receive, 
its  ability  to  produce,  the  effects  of  the  sundry  feeds  upon 
the  health  and  condition  of  the  animal,  upon  its  appetite 
and  taste,  upon  the  quality  of  the  product,  the  money 
values  of  feed,  and  the  profits  to  be  derived  from  their 
use,  are  important  considerations  which  do  not  enter 
into  the  make-up  of  the  physiological  standard,  but  which 
are  vital  factors  in  the  feeder's  problem.  Clearly  the 
physiological  standards  may  supplement,  and  in  some 
measure  guide,  judgment,  but  cannot  take  its  place.'* 


CHAPTER  XVIII 
MAINTENANCE  RATIONS 

IT  has  already  been  shown  that  the  demands  on  the 
food  vary  greatly  with  different  individuals  or  classes 
of  animals  according  to  size  and  the  kind  and  quantity  of 
production.  It  is  proposed  to  indicate  how  rations  should 
be  compounded  in  order  to  meet  varying  conditions  and 
demands  for  production  of  various  kinds,  but  as  prelim- 
inary to  this  an  understanding  should  be  reached  as  to 
what  is  required  to  support  the  producing  organism. 

405.  Definition    of    maintenance    ration. — A   main- 
tenance ration  is  one  supplying  the  needs  of  an  animal 
without  production  of  any  kind  and  with  no  loss  of  body 
substance.    To  be  more  specific,  when  an  ox  doing  no 
work  excretes  just  the  quantities  of  nitrogen  and  carbon 
that  are  contained  in  the  food  consumed,  he  is  said  to  be 
eating  a  maintenance  ration.    The  work  done  by  the 
animal  at  rest  is  largely  needed  in  the  following  direc- 
tions: The  chewing  of  food  and  its  movement  along  the 
intestinal  tract;  the  muscular  action  of  the  heart  in  caus- 
ing blood  circulation;  and  the  metabolic  activity  of  the 
cells  in  causing  the  chemical  transformation  of  the  nu- 
trients.  Some  work  is  also  done  in  moving  the  body  and 
in  the  effort  of  standing.  The  demands  upon  the  food  for 
maintenance    purposes    are    therefore    largely    for    the 
support  of  some  form  of  muscular  activity. 

406.  Character  of  maintenance  ration. — Nine-tenths 
or  more  of  a  maintenance  ration  may  consist  of  carbo- 

(307) 


308  THE  FEEDING  OF  ANIMALS 

hydrates  which,  because  the  income  and  outgo  are  bal- 
anced, are  used  solely  as  fuel.  Only  a  very  small  amount 
of  protein  is  necessarily  destroyed  by  a  resting  animal, 
although  a  minimum  supply  is  absolutely  essential  if  the 
nitrogenous  tissues  of  the  body  are  to  be  kept  from  wast- 
ing. If  an  animal  is  not  eating  protein,  the  cleavage  of 
body  protein  will  go  on  and  urea  will  continue  to  appear  in 
the  urine  and  in  time  protein  starvation  will  cause  death. 

407.  Uses  of  production  ration. — Any  ration,  fed  for 
production,  may  be  looked  upon  as  made  up  of  two  parts, 
that  which  is  needed  to  maintain  the  animal  and  that 
which  may  be  applied  to  growth  or  the  formation  of 
milk  solids.    It  is  possible,  of  course,  for  the  produc- 
tion of  milk  or  wool  to  occur  when  the  cow  or  sheep  is 
fed  what  is  really  only  a  maintenance  ration,  but  the 
materials  for  production  under  these  circumstances  are 
furnished  at  the  expense  of  the  body  substance.    With 
what  is  regarded  as  liberal  feeding,  from  one-third  to 
one-half  of  a  production   ration  is  needed   for  mainte- 
nance purposes.   It  seems  fitting,  then,  to  speak  of  a  main- 
tenance ration  as  a  fundamental  quantity,  a  knowledge 
of  which  is  important  to  both  science  and  practice.   It  is 
clear  that  no  rational  understanding  of  the  uses  of  food 
can  be  had,  unless  we  know  what  amount  is  required 
simply  for  maintenance,  and  the  feeder  is  certainly  helped 
to  a  more  intelligent  compounding  of  rations  if  he  has  some 
means  of  judging  how  large  an  excess  he  is  supplying  for 
production  purposes.    Occasionally,  too,  it  is  desired  to 
provide  horses  and  other  animals  when  not  at  work  with 
just  enough  food  to  keep  them  in  a  uniform  condition 
without  gain  or  loss. 

408.  Maintenance  ration  easily  provided. — No  ration 
is  more  easily  provided  from  the  ordinary  farm  supply 


MAINTENANCE  RATIONS  309 

than  is  that  for  maintenance,  for  two  reasons:  (1)  Because 
the  quantity  of  available  nutrients  which  must  be  eaten 
is  so  small  that  this  ration  may  be  wholly  or  mostly  made 
up  of  bulky  materials  such  as  corn  fodder  and  hay;  (2) 
because  investigation  has  demonstrated  that  mere  main- 
tenance demands  a  comparatively  small  amount  of  pro- 
tein and  so  this  ration  may  have  a  wide  nutritive  ratio 
such  as  pertains  to  the  nutrients  of  the  more  common 
farm  products. 

MAINTENANCE  RATION  FOR  BOVINES 

409.  Various  investigations  concerning  maintenance 
needs. — Experiments,  having  for  their  object  a  determina- 
tion of  the  daily  quantity  of  nutrients  necessary  to  simply 
maintain  animals  of  this  class,  were  conducted  by  Henne- 
berg  and  Stohman  with  oxen  as  long  ago  as  1858.  A  num- 
ber of  rations  were  fed  and  the  conclusions  which  were 
reached  were  based  upon  the  amount  of  food  digested, 
the  gain  or  loss  of  nitrogenous  tissue  by  the  animals, 
their  weights,  and  general  appearance.  The  average  daily 
quantities  of  digestible  nutrients  which  appeared  to  be 
sufficient  to  maintain  a  1,000-pound  ox  without  growth  or 
loss  was  approximately  8.2  pounds,  of  which  .53  pound 
was  protein,  the  whole  having  an  energy  or  heat  value  of 
not  far  from  15,000  calories.  Because  of  the  high  tem- 
perature of  the  stalls  used  in  the  above-named  experi- 
ments, Wolff  estimated  later  that  for  winter  feeding  the 
standard  should  be  8.9  pounds  of  digestible  nutrients,  of 
which  .7  pound  should  be  protein,  the  energy  value  being 
approximately  16,000  calories,  and  for  a  long  time 
Wolffs  figures  were  published  as  the  standard  main- 
tenance ration. 


310  THE  FEEDING  OF  ANIMALS 

This  standard  has  been  revised.  The  earlier  experi- 
ments on  which  it  was  based  furnished  data  insufficient 
for  accurate  conclusions,  for  the  only  means  of  judging 
whether  the  animals  were  gaining  or  losing  body  sub- 
stance were  the  changes  in  live  weight,  which  cannot  be 
regarded  as  conclusive  evidence.  Some  of  the  earlier 
feeding  experiments  conducted  in  the  United  States, 
especially  those  of  Sanborn  and  Caldwell,  indicated  that  a 
ration  based  on  Wolff's  standard  was  capable  of  causing  a 
material  growth  of  steers,  and  the  accuracy  of  Wolff's 
figures  was  called  into  question.  Later  observations  of  a 
more  exact  character  have  shown  quite  conclusively  that 
a  1,000-pound  steer  may  be  maintained  without  loss  of 
body  substances  on  considerably  less  than  8.9  pounds,  or 
even  8  pounds,  of  digestible  nutrients  a  day. 

Elaborate  experiments  by  Kuhn  from  the  years  1882 
to  1890,  afterwards  discussed  by  Kellner,  were  regarded 
by  the  latter  as  justifying  the  conclusion  that  the  mini- 
mum quantity  of  digestible  organic  matter  which  will 
maintain  a  1, 000-pound  mature  ox  at  rest  is  7.3  pounds, 
.7  of  a  pound  of  which  should  be  protein.  Later  Armsby, 
in  presenting  the  results  of  experiments  of  his  own  in 
connection  with  a  critical  review  of  Kiihn's  work,  con- 
cludes that  "we  may  place  the  average  maintenance  of  a 
steer  weighing  500  kgs.  (1,100  pounds)  and  receiving 
only  a  mainly  coarse  fodder  at  13,000  calories  of  availa- 
ble energy."  As  Armsby  has  found  one  gram  of  digesti- 
ble matter  from  roughage  to  be  equal  to  3.5  calories  of 
available  energy,  13,000  calories  would  equal  7  pounds 
of  digestible  matter  from  this  source.  This  would  be 
the  same  as  6.54  pounds  for  a  1,000-pound  animal. 

Still  later,  Kellner,  basing  his  figures  upon  extensive 
researches  by  himself  and  associates,  which  were  the 


MAINTENANCE  RATIONS  311 

most  elaborate  made  up  to  that  time,  gave  us  the 
following  as  the  minimum  quantities  which  will  satisfy 
the  maintenance  needs  of  mature  animals  of  different 
weights: 

Digestible  organic 

Approximate  weight  substance  from 

of  animal  Energy        average  meadow  hay 

Pounds  Calories  Pounds 

1,000 .       .    .  10,740  6.75 

1,100 11,520  7.22 

1,200 .  ;?.    .  12,280  7.72 

1,300 13,010  8.18 

1,400    .    .    . .  ;s 13,720  8.62 

1,500 k   ,   .    .  14,420  9.06 

The  researches  of  Armsby  and  Fries  with  the  respira- 
tion calorimeter,  in  a  study  of  the  fasting  katabolism  of  a 
steer,  furnish  us  data  much  more  reliable  than  can  be 
secured  in  any  other  way. 

410.  Fasting  katabolism  as  a  measure  of  mainte- 
nance needs. — The  exact  maintenance  needs  of  a  given 
animal  are  most  accurately  determined  while  the  animal 
is  fasting.  When  an  animal  is  receiving  no  food  there  is 
no  cessation  of  the  vital  activities.  In  the  maintenance  of 
these  activities  there  is  necessary  a  certain  amount  of 
protein  cleavage  and  a  sufficient  oxidation  of  organic  com- 
pounds to  meet  the  energy  needs  of  the  animal.  The 
material  that  is  so  used  is  taken  from  the  body  structure, 
and  by  determining  the  metabolic  nitrogen  excreted, 
and  the  gaseous  products  resulting  from  oxidation,  the 
exact  maintenance  needs  of  the  animal  are  ascertained. 
This  is  a  determination  of  the  fasting  katabolism  of  the 
animal  body. 

The  investigation  by  Armsby  and  Fries  was  conducted 
with  a  steer  which  first  was  fed  daily  3.2  kilograms  of 
timothy  hay,  an  amount  not  sufficient  to  maintain  the 


312  THE  FEEDING  OF  ANIMALS 

animal  without  loss  of  body  substance.  The  metaboliza- 
ble  energy  of  this  insufficient  ration  was  found  to  be  5.7 
therms,  and  during  the  time  it  was  fed,  the  steer  lost  from 
his  own  tissues  an  amount  of  protein  and  fat  equivalent 
to  2.4  therms  a  day.  In  another  period,  the  steer  ate 
5.2  kilograms  of  the  same  hay,  having  a  metabolizable 
energy  of  9.26  therms,  or  3.58  therms  more  than  was  con- 
tained in  the  smaller  ration.  By  feeding  the  larger  ration, 
the  use  of  body  protein  and  fat  was  reduced  to  .357 
therms  or  2.02  therms  less  than  was  the  case  with  the 
smaller  ration.  It  seems,  then,  that  3.58  therms  of 
metabolizable  energy  in  the  ration  replaced  2.02  therms 
of  energy  derived  from  body  substance;  or,  in  other  words, 
the  metabolizable  energy  in  the  hay  was  only  56.5  per 
cent  as  efficient  as  was  the  energy  derived  from  the 
oxidation  of  body  protein  and  fat.  The  other  43.5  per 
cent  of  the  hay  energy  was  used,  as  we  have  seen,  in  the 
way  of  mastication,  digestion,  and  other  internal  func- 
tions requiring  the  use  of  energy  in  order  to  prepare  the 
food  and  transmit  it  to  the  tissues. 

411.  Distribution  of  maintenance  energy. — A  study 
of  fasting  katabolism  has  made  possible  not  only  the 
energy  used  in  maintenance  but  also  the  approximate 
determination  of  the  distribution  of  the  uses  of  energy. 
Zuntz,  on  the  basis  of  observations  made  with  a  fasting 
man,  computed  that  muscular  activity,  including  circu- 
lation, respiration,  and  the  voluntary  muscles,  used  about 
60  per  cent  of  the  metabolism  and  that  the  internal 
organs,  such  as  the  liver,  intestines,  kidneys,  pancreas, 
and  salivary  glands,  used  about  40  per  cent. 

412.  Use  of  nutrients  in  fasting  metabolism. — The 
studies  of  fasting  metabolism  have  made  it  possible  to 
measure  accurately  the  relative  use  of  the  nitrogenous 


MAINTENANCE  RATIONS  313 

and  the  non-nitrogenous  tissues.  Determinations  with 
many  species  of  animals,  including  man,  swine,  dog, 
rabbit,  guinea  pig,  goose,  and  hen,  show  that  the  protein 
katabolism  in  per  cent  of  total  katabolism  varied  from  7.3 
to  15.6.  In  all  but  two  cases  the  range  was  from  10.8  to 
15.6  per  cent.  This  shows  that  the  energy  derived  from 
the  fat  and  carbohydrates,  largely  from  the  fat  where 
this  has  been  stored,  is  from  six  to  nine  times  as  great  as 
from  the  body  protein. 

413.  Computation  of  maintenance  needs. — The  fore- 
going data  allow  a  computation  of  the  metabolizable 
energy  that  must  be  supplied  in  the  ration  in  order  to 
meet  the  maintenance  needs  of  the  experimental  animal 
that  was  under  observation. 

The  larger  ration  supplied  the  need  of  the  animal  to 
within  .357  therm,  which  was  derived  from  body  sub- 
stance. This  deficit  would  be  equal  to  .632  therm  of 
matabolizable  energy  supplied  by  the  hay.  The  computa- 
tion would  be  as  follows: 

Therms 

56.5  : 100::  357:  z=-=energy 632 

5.3  kilos  hay = energy 9.262 

Energy  needed      9.894 

9.262  therms  :  9.984  therms  ::  5.3  kilos  hay  :  z =5.655  kilos. 
5.655  kilos =12.44  Ibs.  hay,  or  6.34  Ibs.  digestible  nutrients. 

The  animal  weighed  822  pounds.  If  the  animal  had 
weighed  1,000  pounds,  using  the  formula  for  body  sur- 
face, the  figures  for  digestible  nutrients  would  be  7.21 
pounds.  These  figures  correspond  closely  to  those  derived 
from  previous  investigations. 

Armsby  suggests  the  following  maintenance  require- 
ments based  on  production  values  for  cattle,  which 
include  growing  animals: 


314  THE  FEEDING  OF  ANIMALS 

TABLE  LXVIL    MAINTENANCE  REQUIREMENTS  OF  CATTLE 


Live 
weight 
Pounds 
150 

Digestible 
protein 
Pounds 

...        .15 

Energy 
value 
Therms 

1.7 

250      

500     Tt  "-.     -';  v.  -"" 

2 
.    .    »    .                       .3 

2.4 
3.8 

750      
1,000      .  '1           .    ''s 

4 
.  i.   ;'  .           .5 

4.95 
6. 

1,250      . 

6 

7. 

1.500 

.65 

7.9 

414.  Maintenance  rations  for  bovines. — In  order  to 
express  a  maintenance  ration  for  bovines  in  terms  of  hay 
and  grain,  there  are  given  in  this  connection  several  mix- 
tures, based  upon  energy  values  in  Table  XXXIX,  which, 
on  the  basis  of  average  composition  and  digestibility, 
will  furnish  fairly  closely  the  necessary  protein  and  energy: 

To  MAINTAIN  A  1,000-PouND  ANIMAL 

-  ( 12  Ibs.  average  timothy  hay.          /23  Ibs.  mature  corn  silage. 
}  4  Ibs.  wheat  bran.  3<   4  Ibs.  timothy  hay. 

V  2  Ibs.  wheat  bran. 

/8  Ibs.  corn  stover,  much  water.       /5  Ibs.  timothy  hay,  ripe. 
2<  6  Ibs.  clover  hay.  4<J  5  Ibs.  clover  hay. 

(3  Ibs.  corn-and-cob  meal.  v4  Ibs.  corn-and-cob  meal. 

5.  17  Ibs.  good  mixed  hay. 

These  combinations  are  merely  illustrative.  Many  others 
furnishing  an  equivalent  quantity  of  available  nutri- 
ents may  be  used.  Doubtless  these  various  mixtures 
will  not  show  equal  efficiency.  Ration  No.  3  would 
probably  be  more  satisfactory  than  No.  5,  because  of 
greater  palatableness.  All  such  factors  as  the  proportion 
of  grain  in  the  mixture;  the  stage  of  growth  of  the  fodder, 
whether  early  or  late  cut,  immature  or  mature;  the 
amount  of  moisture  present,  as  in  stover;  and  the  com- 
pleteness of  preservation,  will  have  an  influence  upon  the 


MAINTENANCE  RATIONS  315 

nutritive  effect  of  a  ration,  and  these  factors  must  be  con- 
sidered according  to  the  best  judgment  of  the  feeder. 
It  is  possible,  without  question,  to  maintain  an  animal 
on  one  fodder  alone,  such  as  hay,  but  for  several  obvious 
reasons  it  is  better  to  feed  some  grain. 

The  maintenance  rations  heretofore  stated  apply  to 
a  1,000-pound  animal.  For  animals  weighing  more  or 
less  the  quantity  should  be  increased  or  diminished,  but 
not  in  just  the  ratio  in  which  the  animal  varies  in  weight. 

MAINTENANCE  FOOD  FOR  HORSES 

The  general  facts  which  have  been  presented  in  rela- 
tion to  the  function  and  character  of  a  maintenance 
ration  are  as  applicable  to  horses  as  to  bovines.  It  is 
true,  however,  that  rations  simply  sufficient  for  main- 
tenance purposes  have  a  very  limited  application  with 
horses,  because  in  nearly  all  cases  they  are  at  least  used 
for  occasional  driving  or  light  work,  and  even  if  merely 
"boarded,"  regular  exercise  is  necessary  to  their  welfare. 

415.  Studies  of  the  maintenance  needs  of  the  horse. — 
Zuntz,  who  so  thoroughly  studied  the  nutrition  of  the 
horse,  concluded,  after  a  critical  survey  of  the  results  of 
other  men  in  connection  with  the  elaborate  data  from  his 
own  extended  investigations,  that  a  1,000-pound  horse 
can  be  maintained  on  6.4  pounds  of  nutrients,  provided 
the  total  ration  contains  not  more  than  3  pounds  of  crude 
fiber.  This  means  that  the  nutrients  should  come  from  a 
mixture  of  hay  and  grain  if  this  minimum  quantity  is  to 
be  sufficient.  Were  only  hay  to  be  fed,  the  necessary 
nutrients  would  probably  exceed  the  amount  named. 

Grandeau  in  his  experiments  found  that  three  horses, 
whose  mean  weight  was  852  pounds,  were  maintained 


316  THE  FEEDING  OF  ANIMALS 

for  fourteen  months  on  17.6  pounds  of  hay  a  day,  from 
which  the  three  animals  digested  an  average  of  6.06  pounds 
of  organic  matter.  Using  the  method  of  computation 
already  described,  this  is  equal  to  6.75  pounds  of  digesti- 
ble nutrients  for  a  1,000-pound  horse,  a  result  not  greatly 
different  from  that  of  Zuntz. 

The  latest  conclusion  of  Wolff  was  that  a  1,100- 
pound  horse  should  have  for  maintenance  at  rest  7.26 
pounds  of  digestible  organic  matter  daily,  exclusive  of 
the  digested  crude  fiber,  which  would  be  the  same  as 
6.78  pounds  of  fiber-free  nutrients  for  a  1,000-pound 
horse.  As  Wolff  regarded  the  fiber  as  useless  to  a  horse, 
either  for  maintenance  or  for  production  of  work,  the 
last  figures  represent  his  estimate  of  the  maintenance 
needs  of  a  horse  at  rest. 

It  is  proper  to  remark  that  Wolff's  views  as  to  the 
nutritive  value  of  crude  fiber  are  not  generally  accepted. 

The  following  maintenance  standards,  based  on  pro- 
duction values,  are  offered  by  Armsby : 


TABLE  LXVIII. 

Live 
weight 
Pounds 

150     .  :  .  < 

MAINTENANCE  REQUIREMENTS  OF 

Digestible 
protein 
Pounds 

3 

HORSES 

Energy 
value 
Therms 
2. 

250 

.    .4 

2.8 

500      .    .    .    . 

6 

4.4 

750 

.8 

5.8 

1,000 

...  1. 

7. 

1  250 

1.2 

8.15 

1,500 

.  1.3 

9.2 

In  calculating  rations  for  horses,  the  coefficient  of 
digestibility  obtained  in  experiments  with  this  class  of 
animals  should  be  used,  coarse  fodders,  as  stated  pre- 
viously, not  being  so  efficiently  digested  by  horses  as 
by  bovines  or  sheep. 


MAINTENANCE  RATIONS  317 

416.  Maintenance  rations  for  horses. — Accepting  the 
standard  given  on  page  316  as  the  daily  requirement  of  a 
resting  horse,  the  following  rations  would  maintain  a 
1,000-pound  animal  for  one  day: 

-  ( 20  Ibs.  medium  quality  /10  Ibs.  mixed  hay. 

}  mixed  hay.  I  4  Ibs.  bran,  or 


5  Ibs.  oats,  or 
10  Ibs.  timothy  hay.  ^  4  Ibs.  cracked  corn. 

5  Ibs.  oats.  ,m  1U     ,.      ,,     , 

Ibs.  timothy  hay. 


•) 

-n 
i 


lb,  timothy  hay. 

Ibs.  cracked  corn. 

(10  Ibs.  mixed  hay. 

10  Ibs.  medium  mixed  hay.  7<\  10  Ibs.  carrots. 

4^  Ibs.  wheat  middlings  V  4  Ibs.  oats. 

(10  Ibs.  mixed  hay. 
8<  8  Ibs.  carrots. 
\ 


4  Ibs.  bran. 

These  rations  serve  as  examples  and  also  indicate 
how  with  ten  or  twelve  pounds  of  hay  the  several  grains 
mentioned  may  be  combined  to  give  a  maintenance 
ration.  It  is  not  wise  to  feed  a  horse  on  hay  alone,  even 
when  doing  no  work.  Ten  to  twelve  pounds  of  hay  are 
enough  coarse  fodder,  which  may  be  supplemented  to 
advantage  by  both  roots  and  grain. 

417.  Maintenance  food  for  sheep.  —  Basing  his  rec- 
ommendation of  maintenance  rations  for  sheep  upon  Kell- 
ner's  production  values,  Armsby  suggests  the  following: 


Live 
weight 
Pounds 

20         

Digestible 
protein 
Pounds 

23 

Energy 
value 
Therms 
.3 

40     

05 

.54 

60 

07 

.71 

80     

09 

.      .87 

100 

1 

1. 

120     

11 

1.13 

140 

.13 

1.25 

318  THE   FEEDING  OF  ANIMALS 

This  means  that  seven  sheep  weighing  140  pounds 
each,  or  approximately  1,000  pounds,  would  require 
daily  approximately  the  following  quantities  of  food  for 
maintenance  purposes : 

Pounds 

Alfalfa  hay      .    ....<...    '.    .  /. 20 

or 

Clover  hay      .    /  i,  .';.    .,   .  ?,r  .    .  .    *  V'.    .    ...  14 

Rutabagas       .  •  ."".  .  .>  *    .' .  ,    .  ^  ;•  ..- ;.  •'• 14 

Pea  meal     .    ..<-.*".    :    .    .    .    .-.  .    ; 4^ 

or 

Soybean  hay      .   ,   .    .'  '.    ....".• 14 

Rutabagas      .    .    ...    .    .    .    ,    I 14 

Wheat  bran    ./;•......;/:. 5 

These  rations  supply  protein  in  excess  of  the  standard 
given,  but  this  should  not  be  condemned,  as  liberal  allow- 
ance should  be  made  for  the  growth  of  wool. 


CHAPTER  XIX 
MILK  PRODUCTION 

MILK,  like  all  other  animal  products,  is  derived  from 
the  food.  Its  secretion  stands  almost  unrivaled  as  an 
example  of  the  rapid,  extensive,  and  continuous  trans- 
formation of  the  food  into  animal  compounds.  In  no 
other  instance,  except  perhaps  in  the  case  of  the  earliest 
growth  of  animals,  is  so  large  a  proportion  of  the  digested 
nutrients  utilized  in  building  new  material,  or  is  there  so 
intimate  a  relation  between  the  extent  and  kind  of  the 
feeding  and  the  extent  and  character  of  the  resulting 
product.  For  these  and  other  reasons,  the  successful 
feeding  of  milch  cows  requires,  perhaps,  greater  expertness 
and  a  wider  knowledge  of  facts  than  any  other  depart- 
ment of  animal  husbandry.  This  will  appear  more  fully 
as  we  continue  to  develop  this  subject. 

It  is  not  proposed  in  this  connection  to  enter  Into 
an  elaborate  discussion  of  the  chemistry  and  secretion 
of  milk,  for  this  is  presented  elsewhere  in  the  series  of 
which  this  volume  is  a  part.  It  is  essential  to  present 
purposes,  however,  that  .we  call  to  mind  certain  facts 
which  are  pertinent  to  a  consideration  of  the  food  rela- 
tions of  milk  formation. 

418.  Composition  of  cow's  milk. — Milk  is  a  fluid  that 
is  secreted  by  all  mammals  in  a  gland  which  with  the 
cow  is  called  the  udder.  It  contains  water  and  solids,  the 
latter  being  made  up  of  mineral  compounds,  proteins, 
fats,  and  sugar.  The  average  composition  of  normal 

(319) 


320  THE   FEEDING  OF  ANIMALS 

cow's  milk,  excluding  samples  of  unusual  character, 
according  to  a  compilation  by  Van  Slyke  of  5,552  Ameri- 
can analyses  is  as  follows: 

Total  solids        Ash  Proteins          Fats  Sugar  Water 

Per  cent        Per  cent        Per  cent      Per  cent        Per  cent        Per  cent 

12.9  .7  3.2  3.9  5.1  87.1 

The  variations  in  the  composition  of  cow's  milk  are 
large,  the  proportion  of  water  ranging,  under  perfectly 
normal  conditions,  from  84  to  89  per  cent,  with  occa- 
sional analyses  entirely  outside  these  limits.  The  chief 
known  causes  of  such  variations  are  breed,  individuality, 
period  of  lactation,  and  nervous  disturbances.  There 
are  material  daily  fluctuations  as  well,  for  which  no 
reasons  can  now  be  assigned.  These  changes  are  mostly 
in  the  proportions  of  water  and  total  solids,  for  the  com- 
position of  the  solids,  that  is,  the  relative  proportion  of 
proteins,  fats,  and  sugar,  is  remarkably  constant  with 
the  same  animal.  The  effect  of  breed  in  cows  is  illustrated 
by  averages  shown  in  Par.  362.  These  variations  and 
those  due  to  other  causes  are  important  in  considering 
the  relation  of  milk  formation  to  nutrition,  because  the 
food  expense  of  milk  is  determined,  other  things  being 
equal,  not  by  the  volume  but  by  the  milk  solids  elabo- 
rated, for  which  reason  the  draft  upon  the  supply  of 
nutrients,  water  excepted,  is  greater  for  the  secretion  of 
100  quarts  of  Jersey  milk  than  for  the  same  quantity 
of  Holstein  milk.  In  studying  the  economy  of  milk  pro- 
duction, therefore,  we  should  consider  the  relation  of 
food  to  milk  solids  and  not  to  milk  volume. 

419.  Milk  secretion. — There  is  no  milk  in  an  animal's 
food,  that  is  to  say,  hay  and  grain  contain  no  casein, 
butter-fat,  or  milk-sugar.  They  do  contain  nutrients, 
which,  when  subjected  to  the  vital  processes  of  the  animal, 


MILK  PRODUCTION  321 

are  ultimately  transformed  into  the  constituents  of  milk. 
The  mammary  gland  is  not  a  sieve  through  which  cer- 
tain compounds  in  the  blood  are  strained  into  the  udder 
cavities,  but  it  is  a  specialized  tissue  in  which  wonderful 
and  extensive  chemical  changes  occur.  Here,  for  the  first 
time,  we  find  casein,  the  mixture  of  compounds  known 
as  butter-fat,  and  a  sugar  unlike  any  that  is  found  in 
plants,  or  in  any  other  part  of  the  animal  organism. 
Vegetable  fats  contain  glycerides  similar  to  some  of  those 
found  in  milk,  to  be  sure,  but  not  in  the  same  number 
or  proportions.  One  fact,  moreover,  which  dairymen  have 
been  slow  to  recognize  in  all  its  significance,  is  that  the 
udder  of  each  individual  cow  is  a  law  unto  itself  in  the 
characteristics  of  the  milk  which  it  secretes,  and  is  not 
subject  in  any  large  degree  to  control  through  feeding  or 
other  treatment  that  is  not  actual  abuse. 

The  manner  of  milk  secretion  is  something  of  which 
we  know  but  little,  and  this  is,  perhaps,  not  immediately 
important  to  the  dairyman.  The  food  source  of  the  con- 
stituents of  milk  is,  on  the  other  hand,  a  matter  of  great 
practical  interest,  and  here  we  have  information  more  or 
less  definite. 

420.  Food  sources  of  milk  proteins. — The  previous 
discussion  of  the  functions  of  nutrients  must  have  made 
it  clear  that  the  proteins  of  the  milk  can  have  only  one 
source,  viz.,  the  proteins  or  closely  related  compounds  in 
the  food,  a  unanimous  conclusion  which  rests  upon  experi- 
mental evidence  as  well  as  upon  the  universally  accepted 
truth  that  the  animal  organism  does  not  have  the  power 
to  construct  proteins  from  the  simpler  compounds  used 
by  plants  for  that  purpose. 

421.  Food  sources  of  milk-fats. — It  now  seems  quite 
certain  that  the  proteins  are  the  only  constituents  of 

u 


322  THE  FEEDING  OF  ANIMALS 

milk  which  must  have  their  origin  exclusively  in  the 
nitrogen  compounds  of  the  foods,  for  we  have  appar- 
ently sound  reasons  for  believing  that  milk-sugar  and 
the  butter-fats  are  constructed,  in  part  at  least,  from 
carbohydrates.  In  an  investigation  at  the  New  York 
Agricultural  Experiment  Station  as  to  the  food  sources 
of  milk-fat,  two  cows,  both  of  which  gained  materially 
in  live  weight  during  experiments  continuing  two  months 
or  over,  produced  respectively  nineteen  pounds  and  forty 
pounds  more  of  butter-fat  than  could  be  accounted  for 
from  the  food  fat  and  available  proteins.  The  amount 
of  digestible  food  fat  supplied  was  relatively  insignificant 
and  the  secretion  of  milk-fat  seemed  to  be  related  in  no 
direct  way  to  the  protein  exchange.  These  observations 
led  straight  to  the  conclusion  that  carbohydrates  are  milk- 
fat  formers.  The  extent  to  which  food  fat  assists  in  the 
production  of  milk-fat  is  not  yet  determined.  While  the 
ingested  fats  appear  to  pass  directly  into  the  milk  to  some 
extent,  it  seems  quite  evident  that  the  larger  part  of  the 
glycerides  of  milk  have  their  origin  in  the  animal.  We 
are  not  sure,  either,  whether  protein  is  ever  a  source  of 
milk-fat,  but  that  it  is  not  a  necessary  source  now  seems 
to  be  proved. 

422.  The  rate  of  formation  of  milk  solids. — A  cow 
yielding  6,000  pounds  of  average  milk  a  year  is  not 
regarded  as  an  unusual  animal.  This  means,  however, 
the  annual  production  of  not  less  than  780  pounds  of 
milk  solids,  an  amount  at  least  double  the  dry  matter  in 
the  body  of  a  cow  weighing  900  pounds.  When  we  con- 
sider that  this  manufacture  of  new  material  is  carried 
on  not  only  during  a  single  year,  but  through  the  entire 
adult  life  of  the  animal,  we  begin  to  realize  how  exten- 
sive are  the  demands  upon  the  food-supply.  Still  more 


MILK  PRODUCTION  323 

striking  is  the  case  of  high-grade  cows  yielding  annually 
over  half  a  ton  of  milk  solids,  and  when  we  remember 
the  performance  of  Duchess  Skylark  Ormsby,  whose 
27,761  pounds  of  milk  produced  in  one  year  certainly  con- 
tained approximately  3,700  pounds  of  solid  matter  or 
more  than  twice  the  weight  of  the  cow,  we  must  regard 
the  cow  as  possessing  wonderful  powers  of  transmutation. 
Her  capacity  for  the  rapid  and  economical  production  of 
human  food  of  the  highest  quality  is  not  equaled  by  any 
other  animal. 

No  facts  could  more  forcibly  illustrate  the  necessity 
of  liberal  and  proper  rations  for  the  milch  cow. 

423.  Uses  of  nutrients  in  milk  production. — This 
ration  is  used  in  various  directions.  It  must  supply  the 
raw  materials  for  milk  formation,  provide  for  the  growth 
of  the  foetus,  sustain  the  effort  of  milk  secretion,  and 
maintain  the  usual  and  necessary  functions  of  the  animal 
body.  The  nature  and  extent  of  these  uses  are  in  part 
quite  definitely  understood.  First  of  all,  the  kind  and 
quantity  of  milk  solids  may  be  estimated  for  any  given 
case.  The  daily  production  of  30  pounds  of  average  milk, 
a  performance  reasonably  to  be  expected  in  a  good  herd, 
involves  the  elaboration  of  3.87  pounds  of  milk  solids. 
Thirty  pounds  of  high-grade  milk  would  contain  not  less 
than  4.6  pounds  of  solids.  For  mere  maintenance  it  is 
fair  to  assume  that  the  food  requirements  of  the  cow  and 
steer  would  not  be  greatly  unlike,  disregarding  the 
demand  for  energy  utilized  in  milk  secretion,  and  for  the 
material  used  in  the  growth  of  the  young.  On  this  basis 
the  milk  solids  and  the  maintenance  needs  of  a  non-pro- 
ductive cow  call  for  about  11.2  to  12  pounds  of  dry  matter 
daily,  a  quantity  utterly  insufficient,  as  experience  teaches, 
to  maintain  a  cow  giving  30  pounds  of  any  kind  of  milk. 


324 


THE  FEEDING  OF  ANIMALS 


We  are  led  to  the  reasonable  conclusion  that,  outside  the 
building  of  milk  solids,  a  large  expenditure  of  food  energy 
is  required  to  sustain  the  work  of  additional  food  con- 
sumption, the  increased  metabolic  cell  activity  and 
warming  of  the  extra  water  and  food,  which  are  necessarily 
involved  in  milk  secretion.  This  view  is  sustained  by  the 
results  of  investigation.  In  experiments  by  the  writer 
with  two  cows  in  full  flow  of  milk,  which  made  only  a 
slight  gain  in  body  weight,  the  energy  of  the  digestible 
part  of  the  rations  and  of  the  milk  was  determined.  The 
figures  reached  were  approximately  as  follows: 

TABLE  LXIX 


Energy  of  digested  nutrients   .    .    *  '  . 
Energy  of  niilk  solids 

Cow  10 

wt.  775  Ibs. 
Calories 

27,120 
8,450 

Cow  12 
wt.  1,200  Ibs. 
Calories 

31,300 
10200 

Energy  not  used  in  milk      
Maintenance  needs  of  non-productive 
animal     .    .•..'>..- 

18,670 
10,100 

21,100 
13,700 

Balance  of  energy  not  accounted  for          8,570 


7,400 


This  energy  not  accounted  for,  amounting  with  the 
two  cows  to  more  than  one-fourth  the  total  energy  of 
the  nutrients  digested,  may  properly  be  charged  to  the 
work  of  milk  production,  including  of  course,  food  appro- 
priation. Science  and  practice  agree  in  naming  15.5  to 
16.5  pounds  of  digestible  organic  matter  as  approximately 
the  proper  daily  amount  of  digestible  nutrients  for  eco- 
nomical milk  production  with  a  productive  cow  of  aver- 
age size,  much  less  than  which  is  not  to  be  considered  as 
generous  feeding.  The  necessary  supply  of  nutrients  will 
vary  according  to  the  size  and  productiveness  of  the  cow. 
Productivity  independent  of  size  is  a  controlling  factor. 


MILK  PRODUCTION  325 

In  general,  small  cows  eat  proportionately  more  food  than 
larger  ones. 

424.  Protein  requirements  for  milk  production. — The 
question  now  arises,  What  proportion  of  this  quantity 
should  be  protein?  The  actual  amount  of  proteins  in  30 
pounds  of  average  milk,  for  instance,  is  about  1  pound. 
If  .70  pound  is  needed  daily  for  mere  maintenance  then 
1.7  pounds  of  protein  must  be  used  for  maintenance  and 
milk  formation,  a  quantity  which  is  now  regarded  as  too 
small  to  sustain  such  milk  production  when  both  food 
economy  and  the  efficiency  of  the  ration  are  considered. 
With  this  amount  of  protein  in  16  pounds  of  total  digesti- 
ble matter,  the  nutritive  ratio  of  the  ration  would  be 
about  1 : 9.5.  A  ration  with  as  wide  a  ratio  as  this  would 
be  regarded  by  the  great  majority  of  careful  experiment- 
ers, and  most  intelligent  dairymen,  as  less  efficient  than 
one  richer  in  protein.  Few  instances  are  on  record  where, 
in  carefully  conducted  experiment-station  work,  other 
conditions  being  the  same,  a  moderate  ration  with  a 
nutritive  ratio  of  1 : 5.5  to  1 : 6.5  has  not  proved  to  be 
more  efficient  than  one  equivalent  in  quantity  but  with  a 
ratio  materially  wider.  The  observations  of  Atwater 
and  Woods  among  the  dairy  herds  of  Connecticut,  where 
the  owners  were  induced  to  narrow  the  rations  they  were 
found  to  be  using,  gave  emphatic  testimony  as  to  the 
desirability  of  a  larger  proportion  of  protein  than  is 
usually  supplied  in  the  ordinary  home-grown  ration. 

There  are  several  possible  reasons  why  the  protein 
requirement  of  a  non-productive  animal  plus  the  protein 
found  in  the  milk  does  not  constitute  a  proper  standard 
for  a  milk  ration: 

1.  The  stimulating  effect  of  a  generous  supply  of  pro- 
tein upon  metabolic  activity. 


326  THE   FEEDING   OF   ANIMALS 

2.  The  use  of  food  proteins  for  the  synthesis  of  milk 
proteins  over  and  above  in  weight  the  milk  proteins 
actually  formed. 

The  partial  non-availability  of  certain  food  proteins, 
because  of  their  constitution,  for  reconstruction  into 
milk  proteins,  must  now  be  conceded.  (See  Pars.  274, 
275.) 

According  to  the  greater  part  of  testimony  available,  a 
cow  of  average  size  and  capacity  should  receive  at  least 
two  pounds  of  protein  daily  during  the  full  flow  of  milk, 
the  ration  to  have  a  nutritive  ratio  not  wider  than  1 :  6.5. 
The  nutritive  ratio  of  young  pasture  grass,  perhaps  as 
efficient  a  milk-producing  food  as  we  have,  is  even  nar- 
rower than  this,  a  fact  which  doubtless  explains  in  part 
the  large  flow  of  milk  from  abundant  June  pasturage,  and 
which  offers  a  suggestion  for  the  compounding  of  winter 
rations. 

425.  Relative  importance  of  protein  overstated. — 
While  the  importance  of  nitrogenous  feeding-stuffs  to 
a  dairy  herd  is  conceded,  there  is  a  tendency  with  certain 
writers  to  distort  the  relation  of  protein  to  milk  produc- 
tion. Their  utterances  give  the  impression  that  in  feed- 
ing milch  cows,  protein  is  about  the  only  factor  to  be 
considered.  This  view  is  typified  by  the  assertion  that 
"a  cow  gives  milk  only  in  proportion  to  the  protein  that 
she  receives,"  a  remark  which  might  be  made  with  equal 
accuracy  about  carbohydrates.  It  is  true  that  even  if 
carbohydrates  are  supplied  in  abundance,  a  depression 
of  the  protein  below  a  certain  limit  in  a  given  case  will 
diminish  the  milk  flow.  It  is  also  true  that  when  sufficient 
protein  is  fed,  a  reduction  of  the  carbohydrates  below  the 
necessary  quantity  will  cut  down  the  milk  yield.  An  ade- 
quate supply  of  easily  digestible  carbohydrates  is  no  less 


MILK  PRODUCTION  327 

important  physiologically  than  keeping  up  the  necessary 
proportion  of  protein,  though  the  former  may  be  accom- 
plished more  easily  than  the  latter  because  of  the  usual 
character  of  home-raised  crops. 

FEEDING  STANDARDS   FOR  DAIRY  COWS 

The  feeding  standards  for  dairy  cows,  which  are 
regarded  as  embodying  our  most  advanced  knowledge, 
have  been  reached  through  several  stages  of  development. 
The  following  are  brief  descriptions  of  these  stages  with 
suggestions  as  to  their  imperfections: 

426.  Thaer's  hay  values. — Albrecht  Thaer,  known  as 
the  father  of  scientific  agriculture,  more  than  a  half -cen- 
tury ago  suggested  "hay  values"  as  the  basis  for  express- 
ing feeding  standards.    He  calculated  the  relative  values 
of  feeding-stuffs  in  terms  of  good  meadow  hay,  the  neces- 
sary quantities  of  rations  and  substitutions  of  feeding- 
stuffs  in  them  to  be  based  on  such  values.   It  is  now  per- 
fectly understood  how  crude  are  such  standards  for  they 
ignore  the  varying  digestibility  of  feeding-stuffs  and  the 
necessary  relations  in  the  proportion  of  nutrients.    Thaer 
seems  to  have  ignored  weight  and  production  as  factors 
in  determining  what  a  ration  should  be. 

427.  Grouven's    milk-feeding    standards.  —  Grouven 
later  introduced  the  factor  of  weight,  and  formulated 
eight  standards  for  milch  cows  to  be  applied  to  animals 
weighing  from  772  to  1,543  pounds.    The  matter  of  vary- 
ing production  was  ignored.    The  daily  ration  suggested 
for  cows  weighing  1,000  pounds  was  not  irrational,  this 
being:  Dry  matter  28.7  pounds,  crude  protein  2.76  pounds, 
fat  .86  pound,  and  carbohydrates  14.55  pounds,  a  ration 
adequate  to  sustain  a  generous  flow  of  milk. 


328  THE  FEEDING  OF  ANIMALS 

428.  Wolff's  feeding  standard.— Emil  von  Wolff  seems 
to  have  been  the  first  one  to  give  a  definite  recognition 
to  digestibility  as  a  factor  in  calculating  feeding  stan- 
dards. The  standards  he  proposed  were  in  terms  of  digesti- 
ble constituents,  the  quantities  fed  to  be  directly  propor- 
tional to  live  weight  without  reference  to  varying  pro- 
ductivity.   It  was  the  Wolff  standards  that  first  became 
known,  and  somewhat  widely  advocated,  in  the  United 
States.    Then*  advocates  conceded  that  they  were  only 
approximations   to   actual   nutritive   needs   and   chiefly 
valuable  as  suggestions  in  the  compounding  of  rations. 

429.  Kuhn's  feeding  standard.— The  fact  that  Wolff's 
standards  made  no  allowances  for  varying  productivity 
caused  them  to  be  severely  criticised,  and  properly  so. 
The  most  prominent  critic  was  Julius  Kiihn,  who  pro- 
posed a  basal  maintenance  ration,  additions  to  be  made 
to  this  somewhat  in  proportion  to  the  demands  for  pro- 
duction.   The  quantities  of  digestible  nutrients  recom- 
mended by  Klihn  ranged  between  20  and  23.5  pounds  of 
dry  matter,  1.5  and  2 A  pounds  of  digestible  protein  and 
12  to  14  pounds  of  digestible  amides,  crude  fiber,  and 
nitrogen-free  extract,  Kuhn  holding  to  the  point  of  view 
of  his  time  that  amides  function  nutritively  as  do  the 
carbohydrates. 

430.  The    Wolff-Lehman    feeding    standards.  —  The 
first  standards  to  recognize,  in  an  extended  way,  the 
varying  nutritive  needs  of  animals  according  to  produc- 
tion, are  those  known  as  the  Wolff-Lehman,  which  are 
an  attempt  to  so  modify  the  original  Wolff  standards  as 
to  meet  the  requirements  of  cows  of  unlike  productivity. 
This  was  certainly  a  step,  in  the  right  direction. 

These  standards  have  been  widely  used  in  the  litera- 
ture of  animal  nutrition  in  the  United  States. 


MILK   PRODUCTION  329 

431.  American    feeding    standards. — Beginning   with 
the  feeding  standard  suggested  in  1894  by  F.  W.  Woll 
for  dairy  cows,  several  standards  have  been  proposed  by 
American  authors  and  experimenters.    These  proposals 
have  been  based  upon  studies  of  the  practice  of  success- 
ful feeders,  or  upon  more  or  less  extended  feeding  experi- 
ments.   It  cannot  be  said  that  with  a  single  exception 
these  so-called  American  rations  are  based  upon  close 
physiological  studies.    They  are,  in  fact,  mostly  modi- 
fications and  extensions  of  the  Wolff  or  Wolff-Lehman 
standard,  arrived  at  through  a  critical  study  of  what  have 
proved  in  practice  to  be  productive  rations. 

It  is  well  to  submit  these  various  commendable  and 
useful  efforts  to  arrive  at  practical  feeding  standards  to  a 
critical  analysis,  not  only  for  the  purpose  of  presenting 
the  conclusions  reached,  but  also  in  order  to  set  forth  the 
limitations  that  accompany  experimental  work  of  the 
type  upon  which  the  conclusions  were  based. 

432.  WolPs  standard. — This  standard  is  based  upon 
the  average  of  about  100  rations  in  apparently  success- 
ful use  by  American  and  Canadian  farmers.    From  the 
average  was  deduced  the  following  daily  ration  for  milk 
production:  Dry  matter  24.5  pounds,  digestible  protein 
2.15  pounds,  digestible  carbohydrates  and  fat  14.5  pounds. 
This  ration  is  suggested,  apparently,  on  the  assumption 
that  what  is  being  done  by  a  group  of  successful  feeders 
is  a  safe  guide  to  the  practice  of  others.    In  a  sense  this 
is  true,  when  conditions  are  similar.    This  method  of 
reaching  a  conclusion  gives  no  assurance,  however,  that 
the  practice  observed  is  the  best  that  could  be  devised, 
even  though  under  given  conditions  it  may  be  found 
profitable.  Such  a  study  of  existing  practice  is  suggested, 
however. 


330  THE  FEEDING  OF  ANIMALS 

433.  Standards  for  milk  production  based  on 
elaborate  American  feeding  experiments. — Three  in- 
vestigators, Haecker,  Savage,  and  Eckles,  carried  on 
extensive  semi-practical  experiments  for  the  purpose  of 
determining  the  relation  between  the  food  of  a  cow  and 
her  milk  production.  These  several  studies  were  inaugu- 
rated for  practically  the  same  purposes,  viz.,  to  deter- 
mine protein  demand  for  milk  production  and  the  neces- 
sary quantities  of  total  digestible  nutrients.  More- 
over, the  data  secured  have  been  applied  differently 
from  those  derived  from  previous  similar  experimental 
work.  The  final  measurements  have  been  based,  not 
wholly  upon  the  weight  of  the  animal  or  upon  total  milk 
production,  but  also  upon  the  protein  and  total  nutrients 
necessary  for  the  production  of  one  pound  of  milk  with  a 
given  percentage  of  fat.  It  is  on  this  basis  that  these  three 
pieces  of  experimental  work  may  be  compared. 

Haecker  began  his  records  in  1892  and  carried  them 
through,  during  definite  periods,  until  1901.  The  experi- 
ments upon  which  his  final  conclusions  are  principally 
based  were  carried  on  in  1894-1895  for  a  period  of  154 
days,  and  in  1900-1901  for  a  period  of  113  days,  the  num- 
ber of  cows  involved  in  the  first  period  being  12  and  in 
the  last  period  20.  The  fodders  were  analyzed  only  in 
part,  and  the  digestibility  of  the  various  feeding-stuffs 
was  calculated  on  the  basis  of  average  digestion  coefficients, 
with  due  reference  to  the  condition  of  the  coarse  fodders. 

Savage's  work  was  done  from  1909  to  1911.  In  both 
experiments  twelve  cows  were  used  in  three  feeding 
periods  of  six  weeks  each,  production  records  being  kept 
for  five  weeks  in  each  period.  The  fodders  were  analyzed 
but  their  digestibility  was  calculated  from  average  diges- 
tion coefficients. 


MILK  PRODUCTION 


331 


The  experimental  feeding  by  Eckles  was  in  the  years 
1910-1911,  and  his  observations  continued  for  one  year. 
The  various  foods  used  were  analyzed.  Digestion  experi- 
ments were  conducted  during  two  periods,  one  with  three 
animals  while  they  were  on  a  maintenance  ration,  and  one 
with  five  animals  when  near  the  time  of  maximum  milk 
production.  Eckles,  therefore,  secured  rather  more  accurate 
data  than  was  the  case  with  the  other  two  experimenters. 
He  was  able  to  calculate  more  nearly  the  exact  digesti- 
bility of  the  materials  involved  in  the  experimental  work. 

With  all  three  of  these  experiments  the  amount  of 
milk  produced  was  accurately  determined  and  analyses 
made  to  determine  the  percentage  of  fat.  By  ascertain- 
ing, therefore,  the  estimated  or  the  actual  amounts  of 
digestible  material  fed  and  the  milk  production  with  its 
fat-content,  it  was  possible  to  calculate  the  relation  to  the 
product  of  the  protein  and  total  nutrients  digested.  The 
following  table  permits  a  comparison  of  the  recommenda- 
tions of  the  three  experimenters  based  on  the  data  secured. 
A  fuller  table  appears  later.  (See  Appendix.) 

TABLE  LXX.  STANDARDS  FOR  MILK  PRODUCTION  AS  DEVELOPED 
BY  HAECKER,  SAVAGE,  AND  ECKLES.  PROTEIN  AND  TOTAL 
NUTRIENTS  FOR  ONE  POUND  OF  MILK.* 


Per 

Haecker 

Savage 

Eckles 

fat  in 
milk 

Protein 

Total 
nutrients 

Protein 

Total 
nutrients 

Protein 

Total 
nutrients 

Pounds 

Pounds 

Pounds 

Pounds 

Pounds 

Pounds 

3.4 

.0444 

.265 

.0599 

.3115 

.0469 

.285 

3.8 

.0468 

.287 

.0632 

.3369 

.051 

.283 

3.9 

.0474 

.292 

.064 

.3428 

.056 

.298 

5.3 

.0558 

.357 

.0753 

.4209 

.048 

.332 

5.5 

.057 

.366 

.077 

.4311 

.0587 

.396 

6.1 

.0606 

.392 

.0818 

.4619 

.072 

.505 

*In  excess  of  maintenance  needs. 


332  THE  FEEDING  OF  ANIMALS 

The  figures  here  given  represent  the  actual  use  of  nutri- 
ents by  the  several  animals  in  Eckles'  experiment,  and 
not  the  suggested  standards.  These  follow : 

Total  Total 

Protein  nutrients  Protein  nutrients 

Pounds  Pounds  Pounds  Pounds 

.05  .26  .062  .36 

.052  .28  .066  .4 

.955  .3  .07  .45 

.058  .33  .075  .5 

These  figures  are  calculated  on  the  basis  of  the  nutrients 
fed  minus  the  nutrients  necessary  for  the  maintenance  of 
the  animal  without  production.  Students  of  these  figures 
should  bear  in  mind  that  in  these  investigations  the  only 
measures  of  the  efficiency  of  the  rations  have  been  the  milk 
production  and  the  changes  in  weight  of  the  animals.  It 
is  evident  that  it  was  not  possible  by  the  methods  used 
to  determine  whether  there  was,  with  a  given  animal,  a 
gam  or  loss  of  body  substance  other  than  would  be 
indicated  by  a  change  in  weight,  which,  as  is  well  known, 
is  often  a  deceptive  standard  of  measurement.  It  should 
be  said,  however,  that  probably  no  practical  feeding 
experiments  with  dairy  cows  so  far  conducted  give  figures 
more  reliable  as  a  guide  to  the  feeding  of  dairy  animals 
than  those  above  cited.  It  will  be  noted  that  the  increase 
in  the  protein  and  total  nutrient  requirement  for  each 
increase  of  one-tenth  per  cent  fat  in  milk  is  as  follows : 

Haecker         Savage 
Pounds         Pounds 

Average  protein  increase  for  .1  per  cent  of  fat 

in  milk 0006         .0008 

Average  total  nutrient  increase  for  .1  per  cent 

of  fat  in  milk 0048         .0056 

434.  Requirements  of  certain  feeding  standards  for 
dairy  cows. — In  order  to  apply  the  various  standards  for 


MILK  PRODUCTION 


333 


feeding  dairy  cows  that  have  been  set  forth,  it  is  neces- 
sary first  to  determine  what  the  standards  require.  These 
requirements  for  a  1,000-pound  cow  giving  thirty  pounds 
of  5  per  cent  milk  would  be  as  follows: 

TABLE  LXXI 


Maintenance 

Production 

Total 

Protein 

Total 
nutrients 

Protein 

Total 
nutrients 

Protein 

Total 

nutrients 

Pounds 

Pounds 

Pounds 

Pounds 

Pounds 

Pounds 

Wolff-Lehman§ 

.7 

8.22 

2.6 

9.88 

3.3 

18.1 

Haecker    .    .  '. 

.7 

7.92 

1.62 

11.19 

2.32 

19.11 

Savage  .    .  .''.    .' 

.7 

7.92 

2.18 

12.14 

2.88 

20.06 

In  the  next  table  are  given  the  energy  equivalents  of 
the  nutrients  required  by  the  several  standards: 

TABLE  LXXII 


Maintenance 

Production 

Total 

Protein 

Energy* 

Protein 

Energy* 

Protein 

Energy* 

Pounds 

Therms 

Pounds 

Therms 

Pounds 

Therms 

Wolff-Lehman§ 

.7 

13.05 

2.6 

15.685 

3.3 

28.735 

Haecker    .    .    . 

.7 

12.573 

1.62 

17.765 

2.32 

30.338 

Savage  .... 

.7 

12.573 

2.18 

19.273 

2.88 

31.843 

Armsbyll   .  \  .    . 

.51 

6.». 
.1 

1.35} 

11.7f 

1.85J 

17.7t 

*Metabolizable. 

f'et  energy, 
rue  protein, 
or  27.5  pounds  of  milk  daily,  per  cent  fat  not  given. 
Ider  production  values  used. 

435.  Calculation  of  rations  for  dairy  cows.— In  order 
to  determine  what  a  ration  should  be  for  this  particular 
animal,  use  is  made  of  the  following  figures  showing  the 
digestible  protein  and  total  digestible  nutrients  in  the 
various  feeds  entering  into  the  combinations  that  are 
suggested : 


334 


THE  FEEDING  OF  ANIMALS 


TABLE  LXXIIL    IN  100  POUNDS 


Digestible 
protein 

Total 
digestible 
nutrients* 

Corn  silage 

Pounds 
1.1 

Pounds 

177 

Timothy     "  
Alfalfa  hay 

3. 
106 

48.5 
51  6 

Corn  meal      

6.9 

838 

Wheat  middlings       

13.4 

69.3 

Gluten  feed    
Cottonseed  meal    

21.6 
33.4 

80.7 
75.5 

"Carbohydrates  +  (Fat  X  2.25)  +Digestible  protein. 

The  next  table  shows  the  rations  that  would  meet 
the  demands  of  each  of  the  five  standards  that  have 
been  suggested,  three  of  these  rations  corresponding  to 
the  several  standards  for  feeding  a  1,000-pound  cow  giving 
thirty  pounds  of  5  per  cent  milk: 

TABLE  LXXIV 


Wolff- 
Lehman 

Haecker 

Savage 

Armsby 

J 

3 

zP.f 

I 

-2 
III 

5*1 

Ration 

»l 

§ 

1 

Diges- 
tible 
nutrients 

Silage  
Timothy  hay  
Alfalfa  hay  
Corn  meal  
Wheat  middlings  .  .  . 
Gluten  feed 

Lbs. 
40 

Lbs. 
7.08 

Lbs. 
40 

Lbs. 
7.08 

Lbs. 
40 

Lbs. 
7.08 

Lbs. 
40 
8 

6 
4 
2 

48 
12 

Lbs. 
7.08 
3.88 

5.03 

2.77 
1.61 

1.85* 
20.37 

6 

4 

3 
3 
46 
10 

3.09 
3.35 

2.42 
2.26 

3.01 
18.2 

8 
6 
3 

1 

48 
10 

4.13 
5.03 
2.08 

'.75 

2.44 
19.1 

8 
5 
1 
3.5 
1.5 
48 
11 

4.13 
4.19 
.69 
2.82 
1.13 

2.92 
20.04 

Cottonseed  meal  .  .  . 
Roughage  
Grain  
Protein  
Digestible  nutrients.total 

True  protein. 


MILK  PRODUCTION  335 

It  is  to  be  noted  that  these  several  rations  do  not 
differ  essentially  in  quantity  but  show  some  variations  in 
the  proportions  of  the  several  ingredients  in  order  to 
reach  an  adjustment  with  the  protein  requirement.  The 
quantities  of  the  several  feeds  in  the  Armsby  standard 
are  based  upon  the  production  values  which  he  has  set 
forth.  (See  Par.  263.)  The  Wolff-Lehman  ration  is  based 
upon  the  standard  for  a  1,000-pound  cow  giving  27.5 
pounds  of  milk,  the  fat  content  not  stated. 

It  should  be  remarked  that  these  rations  would  be 
regarded  by  practical  feeders  as  sufficiently  generous.  It 
is  a  question  whether  the  amount  of  protein  required  by 
the  Wolff-Lehman  and  Savage  standards  are  not  unneces- 
sarily generous,  a  point  to  be  considered  when  protein 
feeds  are  more  costly  than  feeds  bearing  a  large  propor- 
tion of  carbohydrates. 

436.  Suggested  practical  rations  for  dairy  cows. — 
The  following  are  suggested  as  practical  rations  for  cows 
of  moderate  size  and  fairly  large  productive  capacity: 

'10  Ibs.  clover  hay.  flO  Ibs.  mixed  meadow  hay. 

1 35  Ibs.  corn  silage.  1 40  Ibs.  corn  silage. 

l{   2  Ibs.  hominy  chops.  2-j   4  Ibs.  wheat  middlings. 
Ibs.  wheat  bran.  I   3  Ibs.  maltsprouts. 

Ibs.  Unseed  meal,  N.P.  V  1  Ib.  gluten  meal. 

f  6  Ibs.  clover  hay.  10  Ibs.  corn  stover. 
10  Ibs.  mixed  meadow  hay.  5  Ibs.  alfalfa  hay. 

25  Ibs.  mangels.  4<  25  Ibs.  sugar-beets. 

3<{    3  Ibs.  corn  meal.  3  Ibs.  corn-and-cob  meal. 

2  Ibs.  wheat  bran.  3  Ibs.  buckwheat  middlings. 

2  Ibs.  brewers'  grains.  \1A  Ibs.  cottonseed  meal. 

2  Ibs.  gluten  meal. 

'12  Ibs.  clover  or  alfalfa  hay. 
30  Ibs.  corn  silage. 

4  Ibs.  ground  oats. 

3  Ibs.  ground  peas. 

2  Ibs.  brewers'  grains. 


336  THE  FEEDING  OF   ANIMALS 

These  rations  may  be  criticized  on  the  ground  that 
they  are  too  small  to  sustain  heavy  milk  production. 
This  would  be  a  i,ust  criticism  for  cows  of  large  capacity 
that  are  furnishing  high-priced  milk. 

It  is  the  writer's  opinion  that  a  majority  of  cows  not 
over  1,000  pounds  in  weight,  maintained  under  ordin- 
ary business  conditions,  will  not  render  larger  profit  from 
heavier  rations. 

437.  The  sources  of  commercial  protein  for  milk  pro- 
duction :  the  home  supply. — The  dairyman  has  constantly 
to  face  the  fact  that  from  the  usual  list  of  home-grown 
feeding-stuffs  it  is  difficult  to  make  up  a  ration  through- 
out an  entire  season  with  a  nutritive  ratio  much  narrower 
than  1:8,  and  a  proportion  of  protein  even  as  high  as 
this  requires  a  generous  admixture  of  clover  hi  the  hay, 
and  the  use  of  more  or  less  oats  or  peas  hi  the  grain  ration. 
It  should  not  be  forgotten  that  the  plants  used  for  for- 
age crops  are  generally  not  harvested  until  they  are 
approaching  maturity,  and  as  the  later  growth  of  most 
plants  is  largely  due  to  the  formation  of  non-nitrogenous 
compounds,  the  hay  and  other  fodders  stored  for  winter 
feeding  are  comparatively  poor  in  nitrogen  compounds. 
On  those  farms  where  the  hay  crop  comes  largely  from 
the  true  grasses,  like  timothy  and  red-top,  and  where  the 
corn  crop  is  a  prominent  feature,  a  home-raised  winter 
milk  ration  having  a  maximum  efficiency  for  each  unit  of 
dry  matter  consumed  is  not  possible.   On  the  other  hand, 
where  alfalfa  and  clovers  constitute  a  good  proportion 
of  the  hay,  and  where  generous  areas  c-f  peas  and  oats 
are  grown,  a  ration  compounded  from  home  resources 
may  have  a  high  milk-producing  efficiency. 

438.  Commercial    protein. — It    must    be    confessed, 
however,  that  most  dairy  farms  are  lacking  in  a  proper 


MILK  PRODUCTION  337 

home-raised  supply  of  the  more  nitrogenous  feeding- 
stuffs,  and  as  nearly  all  dairymen  depend  to  come  extent 
upon  purchased  grain,  it  is  a  quite  prevalent  custom  for 
them  to  seek  those  by-products  that  will  strengthen  the 
protein  side  of  the  ration.  It  is  unquestionably  true  that 
farmers  should  be  more  independent  of  the  markets,  and 
they  certainly  may  be  if  an  intensive  system  of  cul- 
tivating well-selected  crops  is  adopted;  but  so  long  as 
more  or  less  grain  will  certainly  be  purchased,  it  is  wise 
to  consider  the  matter  of  selecting  commercial  protein 
feeds  for  dairy  cows.  Those  from  which  it  is  possible  to 
choose  are  the  oil  meals,  distillers'  grains,  the  gluten 
meals  and  feeds,  brewers'  grains,  maltsprouts,  peas,  and 
buckwheat  middlings.  The  offals  from  the  milling  of 
wheat,  while  somewhat  more  nitrogenous  than  the  cereal 
grains,  cannot  be  considered  as  an  abundant  source  of 
protein,  although  they  are  excellent  components  of  a 
milk  ration. 

439.  No  single  protein  food  essential. — Notwith- 
standing the  claims  which  trade  interests  may  make  to 
the  contrary,  no  one  of  the  above-mentioned  feeding- 
stuffs  is  alone  essential  to  the  economical  production  of 
the  best  of  milk.  There  is  no  single  food  or  any  one  com- 
bination of  foods  that  is  always  best  for  dairy  cows. 
Apart  from  certain  considerations  which  will  be  discussed 
later,  a  selection  of  the  source  of  commercial  protein  is  a 
matter  of  availability  and  of  relative  market  cost.  For 
instance,  if  gluten  meal  were  to  cost  $30  a  ton,  few 
buyers  could  afford  to  pay  $35  for  linseed  meal  to  feed  in 
any  considerable  quantity.  If  prices  were  reversed,  oil 
meal  should  be  selected.  Both  oil  meals  and  gluten  prod- 
ucts may  be  ignored  if  buckwheat  middlings  or  the 
brewers'  residues  are  available  at  more  favorable  prices. 


338  THE  FEEDING  OF  ANIMALS 

It  is  simply  necessary  that  the  grain  ration  shall  con- 
tain protein  in  sufficient  quantity  and  proportion,  and 
shall  be  made  up  of  a  variety  of  materials,  better  not 
less  than  three  kinds,  all  of  which  should  be  palatable 
and  exert  no  deleterious  influence  upon  the  milk  or  its 
products.  There  are  few  grain  products  that  cannot  be 
used  successfully  in  grain  mixtures,  even  though  they 
are  undesirable  when  fed  alone. 

THE   RELATION   OF   FOOD   TO   THE    COMPOSITION  AND 
QUALITY  OF  MILK 

The  character  of  milk  is  believed  by  many  to  be  inti- 
mately related  to  the  kind  and  quantity  of  food  from 
which  it  is  produced,  i.  e.,  that  a  dairyman  who  is  pos- 
sessed of  sufficient  knowledge  may,  by  variations  in  the 
rations,  cause  material  changes  in  the  composition  of 
the  milk  of  his  herd.  This  is  equivalent  to  believing  that 
thin  milk  or  rich  milk,  milk  rich  in  fats  and  poor  in  casein 
or  the  reverse,  may  be  obtained  at  the  will  of  the  feeder. 
Such  a  view  in  its  extreme  form  is  very  far  from  the 
truth.  While  below  a  certain  limit  for  each  cow  the  quan- 
tity of  milk  is  mostly  determined  by  the  ration,  other 
factors,  such  as  breed,  individuality,  and  period  of  lac- 
tation, are  much  more  potent  than  the  food  in  fixing 
its  composition. 

In  discussing  this  topic,  it  must  be  confessed,  first 
of  all,  that  the  experiments  touching  its  several  phases 
have  not  furnished  information  satisfactorily  definite 
and  conclusive  in  all  respects.  The  testimony  arrived  at 
is  more  or  less  confusing  and  contradictory.  There  are 
several  directions  in  which  it  has  been  necessary  to  look 
for  the  effect  of  food  upon  milk:  (1)  Effect  upon  composi- 


MILK  PRODUCTION  339 

tion:  (a)  in  changing  the  proportion  of  water  and  total 
solid  matter;  (6)  in  changing  the  relative  proportions  of 
proteins,  fat,  and  sugar,  (c)  in  changing  the  constituents 
of  the  fat.  (2)  Effect  upon  flavor. 

440.  Effect  of  food  on  the  proportion  of  milk  solids. 
— In  discussing  the  effect  of  food  upon  the  proportion 
of  total  solids,  the  question  is,  Can  the  richness  of  milk 
be  modified  by  changes  in  the  ration?  For  instance,  is 
the  milk  from  a  very  generous  food-supply  richer  than  that 
from  a  moderate  or  scanty  ration,  or  will  a  highly  nitrog- 
enous ration  cause  a  secretion  of  milk  with  a  higher  per- 
centage of  solids  than  a  ration  poor  in  protein?  It  would 
probably  be  generally  conceded  that  if  variations  in  milk 
are  caused  in  these  ways,  they  are  small  as  compared  to 
those  due  to  breed  characteristics  or  to  individuality. 
Can  we  bring  about  variations  sufficiently  large  to  be 
important?  This  question  has  been  much  discussed  and 
much  investigated  from  the  work  of  Kuhn  in  1868  down 
to  the  present  day.  Many  experiments  have  been  con- 
ducted for  long  periods  and  short  periods  in  which  very 
moderate  rations  have  been  compared  with  very  large 
ones,  highly  nitrogenous  foods  with  those  of  a  low  pro- 
tein-content, dry  with  green  or  succulent  materials,  and 
grains  of  the  same  class  with  one  another,  and,  in  a  great 
majority  of  cases,  the  verdict  has  been  that  no  consist- 
ent relation  appears  to  exist  between  the  quantity  or 
character  of  the  ration  and  the  proportion  of  solids  in 
the  milk,  a  conclusion  that  has  run  counter  to  a  very  per- 
sistent popular  belief.  In  some  cases,  a  temporary  change 
has  appeared  in  the  milk  immediately  after  a  violent  change 
in  the  ration,  but  in  most  instances  of  this  kind,  there  was 
very  soon  a  return  to  the  animal's  normal  product.  In 
a  small  proportion  of  experiments,  the  milk  appeared  to 


340  THE  FEEDING  OF  ANIMALS 

sustain  a  permanent,  though  not  extensive,  modification. 
The  weight  of  testimony  bears  out  the  statement  that 
the  content  of  solids  in  milk  cannot  be  modified  at  will 
by  the  farmer,  but  is  largely  determined  by  causes  not 
under  his  control,  such  as  breed  and  individuality, 
although  feeding  and  treatment,  especially  the  latter, 
have  more  or  less  influence  upon  the  character  of  the 
milk  secreted.  It  is  possible,  even  probable,  that  continu- 
ous feeding,  either  very  poorly  or  very  highly,  may  bring 
about  in  time  a  permanent  change  in  a  cow's  milk,  but 
today  no  one  is  wise  enough  to  point  out  a  way  of  defin- 
itely controlling  this  product  through  the  food. 

441.  Effect  of  food  upon  the  constitution  of  milk 
solids. — In  the  discussions  relative  to  feeding  dairy  cows, 
another  point  has  received  much  attention,  viz.,  the 
effect  of  foods  upon  the  proportions  of  the  constitu- 
ents which  make  up  the  dry  matter  of  milk.  A  popular 
notion  has  prevailed  that  it  is  possible  to  "feed  fat  into 
milk,"  having  its  origin  in  part,  perhaps,  in  miscon- 
ceptions as  to  the  manner  of  milk  formation.  If  the 
mammary  gland  served  simply  to  capture  the  unchanged 
constituents  of  the  food,  then  it  might  be  reasonable  to 
expect  the  milk  to  partake  of  the  character  of  the  digested 
nutrients  and  be  "fat"  or  "lean"  according  to  the  pro- 
portions of  proteins  and  fats  supplied  to  the  animal. 
When,  however,  we  consider  that  this  gland  has  the  func- 
tion of  transforming  the  raw  material  of  the  food  into  a 
milk  which  is  characteristic  of  the  breed  or  of  the  individual 
in  accordance  with  somewhat  fixed  constitutional  limi- 
tations, and  that  from  the  same  food  the  Jersey  cow  will 
make  Jersey  milk  and  the  Holstein  cow  Holstein  milk, 
that  a  cow  which  starts  in  life  giving  thin  milk  is  never 
transformed  into  a  producer  of  rich  milk,  we  can  easily 


MILK  PRODUCTION  341 

understand  the  general  failure  to  find  a  recipe  for  feed- 
ing fat  into  milk.  Experimenters  who  have  added  large 
quantities  of  fat  or  oil  to  a  ration  have  in  all  but  a  very 
few  instances  failed  to  permanently,  or  even  tempora- 
rily, increase  the  percentage  of  fat  in  the  milk  solids; 
and,  on  the  other  hand,  rations  rich  in  protein  do  not 
appear  to  cause  a  larger  relative  amount  of  proteins  in 
the  milk-dry  substance  than  rations  with  a  wide  nutri- 
tive ratio.  As  a  matter  of  fact,  after  years  of  investiga- 
tion and  intelligent  observation,  we  are  not  able  to  affirm 
that  the  proportion  of  fat  to  other  milk  solids  is  in  any 
way  related  to  the  feeding  of  the  cow,  and  if  apparent 
exceptions  to  the  general  experience  have  been  noticed, 
no  one  has  discovered  any  general  method  or  law  whereby 
the  exception  may  be  made  the  rule. 

Physiological  disturbances  may  result  from  feeding  a 
ration  so  selected  or  treated  that  it  is  greatly  deficient 
in  certain  nutrients.  In  experiments  by  Jordan,  Hart, 
and  Patten,  the  deficiency  of  phosphorus  compounds 
in  the  rations  of  milch  cows  appeared  to  cause,  among 
other  effects,  a  marked  diminution  of  the  proportion  of 
fats  in  the  milk  solids.  By-product  feeding-stuffs  simi- 
larly deficient  might  cause  a  similar  result. 

442.  Influence  of  food  on  the  milk-fats. — It  should 
not  be  inferred  from  the  previous  statements  that  none 
of  the  compounds  of  the  food  enter  the  milk  as  such,  or 
that  the  qualities  of  the  milk  are  in  no  way  influenced 
by  the  character  of  the  ration.  Such  conclusions  would 
not  be  consistent  with  the  outcome  of  numerous  investiga- 
tions. While  it  has  become  quite  evident  that  the  com- 
position of  butter,  and  therefore  its  qualities,  such  as 
hardness  and  melting-point,  are  sometimes  materially 
modified  by  the  cow's  food,  it  is  not  now  possible  to  state 


342  THE  FEEDING  OF  ANIMALS 

with  any  definiteness  just  what  influence  all  the  various 
feeding-stuffs  have  upon  the  chemical  and  physical 
properties  of  butter.  Experimenters  are  fairly  unani- 
mous, however,  in  concluding  that  the  liberal  feeding 
with  cottonseed  or  cottonseed  meal  has  the  effect  of 
raising  the  melting-point  of  butter  and  of  diminishing 
the  percentage  of  the  volatile  fatty  acids.  On  the  other 
hand,  when  gluten  meal  rich  in  oil  has  been  introduced 
into  the  ration  in  generous  proportion,  the  butter  has 
been  found  to  melt  at  a  lower  point,  and  appeared  softer. 
Certain  chemical  reactions  indicate  that  this  decrease  in 
the  melting-point  has  been  accompanied,  in  some  cases  at 
least,  by  an  increase  in  the  butter  of  olein,  a  fat  which  is 
a  prominent  constituent  of  olive  oil,  and  is  liquid  at 
ordinary  temperatures.  One  set  of  experiments,  where 
gluten  meal  with  different  proportions  of  oil  was  used, 
appears  to  warrant  the  conclusion  that  the  softening  of 
the  butter  from  feeding  this  material  is  not  marked  when 
its  percentage  of  fat  is  small,  as  is  the  case  with  some 
brands  of  gluten  meal  at  the  present  time.  The  conclu- 
sion which  has  been  reached  as  a  result  of  some  experi- 
ments, that  gluten  meal  causes  softer  butter  than  corn 
meal,  the  fats  and  other  compounds  in  the  two  feeds 
being  similar  in  kind,  is  wholly  irrational  unless  we 
conclude  that  the  larger  quantity  of  fat  fed  in  the  former 
is  the  cause  of  its  specific  influence.  In  a  few  cases  where 
various  oils  were  fed  in  liberal  quantity  the  butter  is 
reported  to  have  varied  in  ways  corresponding  to  the 
composition  of  the  oils,  a  result  not  at  all  improbable. 

In  looking  over  the  record  of  investigations  along 
this  line  it  is  found  that  food  rich  in  sugar  and  other 
soluble  carbohydrates  is  credited  with  producing  soft 
butter,  potatoes  are  charged  with  the  .same  effect,  and 


MILK  PRODUCTION  343 

even  cooked  or  sour  foods  are  said  to  have  a  peculiar 
influence.  Some  writers  go  so  far  as  to  present  lists 
of  feeding-stuffs  in  the  order  in  which  they  increase  the 
volatile  fatty  acids,  but  such  definite  representations  must 
at  present  be  taken  "with  a  grain  of  salt."  In  most 
instances,  no  relation  is  established  between  the  effect 
observed  and  the  market  value  of  the  butter.  In  fact,  it 
is  distinctly  asserted  by  one  or  two  experimenters  that 
there  is  no  clear  relation  between  the  melting-point  and 
hardness.  It  seems  quite  probable  that  when  the  ration 
includes  a  variety  of  grain  foods,  practically  the  entire 
list  of  feeding-stuffs  may  be  utilized  under  proper  con- 
ditions without  damaging  the  market  value  of  the  butter 
for  local  consumption. 

443.  Effect  of  food  on  the  flavors  of  milk  and  its 
products. — It  is  not  possible  with  our  present  knowl- 
edge to  establish  a  relation  between  the  flavors  of  dairy 
products  and  the  presence  of  definite  compounds.  What- 
ever causes  flavor  in  milk  or  butter  is  generally  present 
in  such  minute  quantities  that  even  if  the  nature  of  the 
substance  were  known  the  determination  of  its  amount 
would  be  beyond  the  skill  of  the  chemist.  Milk  satis- 
factory to  the  critical  taste  and  smell  may  be  so  simply 
because  bad  flavors  are  absent,  or  there  may  be  present 
the  positive  influence  of  some  constituent  of  the  ration. 
It  is  probably  safe  to  assert  that  compounds  in  the  food 
pass  into  the  milk  as  such,  and  the  superiority  of  June 
butter,  if  such  exists,  may  be  due  to  the  almost  impon- 
derable volatile  odors  which  are  derived  from  the  young 
grasses.  Nothing  is  more  certain  than  that  the  dele- 
terious odors  of  certain  foods  and  those  that  pertain  to 
the  stable  are  often  absorbed  by  milk,  as,  for  instance, 
when  cabbage,  turnips,  and  onions  are  fed. 


344  THE  FEEDING  OF  ANIMALS 

It  is  generally  believed  that  odors  or  flavors  from 
the  foods  which  affect  milk  in  so  marked  a  manner  may 
enter  it  in  two  ways,  by  transference  through  the  animal 
and  by  absorption  from  the  air  of  the  stable.  Unfortu- 
nately, however,  the  various  views  which  are  accepted 
regarding  this  matter  are  not  based  upon  satisfactory 
experimental  evidence.  Some  farmers  declare  in  most 
positive  terms  that  they  can  feed  turnips  to  their  cows 
with  no  harm  to  the  quality  of  the  butter,  while  others 
assert  that  this  cannot  be  done.  It  is  claimed  that  the 
time  of  feeding,  whether  just  before  or  just  after  milk- 
ing, has  a  marked  influence  upon  the  extent  to  which 
turnips  and  similar  materials  impart  a  flavor  to  the  milk. 
Concerning  all  these  points,  we  have  but  little  evidence 
other  than  the  somewhat  loose  observations  of  practice. 

The  results  of  certain  experiments  are  worthy  of  men- 
tion in  this  connection.  King  and  Farrington,  of  the  Wis- 
consin Experiment  Station,  declare  that  their  experi- 
ments show  beyond  question  that  when  silage  is  fed 
before  cows  are  milked  a  sweetish  flavor  is  imparted  to 
the  milk,  and  that  such  a  flavor  is  not  detected  when  the 
silage  is  fed  after  milking.  These  experimenters  also 
placed  milk  within  a  silo  exposed  to  the  air  for  an  hour, 
and  silo  air  was  forced  through  the  contents  of  some  cans. 
In  seven  out  of  twenty  tests  no  silage  odor  could  be 
detected,  and  it  was  less  in  any  case  than  when  silage  was 
fed  before  milking. 

Canadian  experiments  on  the  effect  of  feeding  tur- 
nips seemed  to  warrant  the  conclusion  that  the  mere 
presence  of  a  strong  turnip  flavor  in  the  stable  did  not 
affect  the  milk,  and  that  when  the  turnips  were  fed  in 
small  quantity  (one  peck)  daily  no  flavor  was  imparted, 
but  that  when  one  bushel  or  more  was  given  the  flavor 


MILK  PRODUCTION  345 

appeared  whether  the  turnips  were  fed  before  milking 
or  after.  On  the  other  hand,  in  a  Norwegian  experi- 
ment as  high  as  2.8  bushels  of  turnips  were  fed  to  cows 
daily  and  no  turnip  taste  could  be  detected  in  the  milk. 
The  cows  were  fed  in  one  place  and  milked  in  another, 
and  so  the  experimenter  concluded  that  when  this  taste 
is  observed  it  is  due  to  absorption  by  the  milk  after  it  is 
drawn.  That  warm  milk  may  absorb  odors  is  shown  by 
Russell.  These  observations  illustrate  fairly  the  some- 
what inconclusive  state  of  the  testimony  on  the  points 
in  question. 


CHAPTER  XX 
FEEDING  GROWING  ANIMALS 

A  DISCUSSION  of  rations  for  growing  animals  relates  in 
large  part  to  the  uses  of  food  for  constructive  purposes. 
The  formation  of  bone  and  soft  tissue  proceeds  rapidly 
in  the  young  organism,  the  nutrition  of  which  must  be 
adapted  in  kind  and  quantity  to  large  demands  in  this 
direction.  This  is  true  of  all  young  domestic  animals. 

444.  The  requirements  for  growth. — The  actual  daily 
increase  in  live  weight  of  a  well-nourished  calf  may  be  as 
great  as  that  of  a  mature  steer  when  liberally  fed.  It  is 
not  unusual  for  the  former  to  gain  two  pounds  a  day  in 
weight,  and  1.5  pounds  is  less  than  would  be  satisfactory. 
It  is  possible  to  calculate  approximately  what  this  growth 
would  require  of  actual  dry  matter.  The  only  analysis 
of  a  calf's  body  which  is  available  is  that  made  by  Lawes 
and  Gilbert,  from  which  it  appears  that  the  entire  animal 
when  fat  has  approximately  the  following  composition: 

Water  Ash  Protein  Fat 

Per  cent  Per  cent  Per  cent  Per  cent 

64.6  4.8  16.5  14.1 

A  gain  of  1.5  to  2  pounds  live  weight  means  a  storage  of 
not  less  than  .24  to  .33  pound  of  dry  protein  in  the 
animal's  body,  and  the  laying  on,  when  the  animal  is  fed 
for  fattening,  of  .21  to  .28  pound  of  actual  fat.  Here, 
then,  is  an  actual  daily  increase  of  dry  body  substance 
of  .45  to  .61  pound,  which  may  be  equal  to  one- 

(346) 


FEEDING  GROWING  ANIMALS  347 

fifth  or  more  of  the  total  dry  substance  of  the  ration  for 
a  very  young  animal. 

445.  Food  freely  appropriated  by  growing  animal. — 
More  definite  information  is  furnished  by  the  somewhat 
limited  studies  which  have  been  made  of  the  metabolism 
of  the  calf.    As  long  ago  as  1878  Soxhlet  studied  the 
income  and  outgo  of  three  young  calves  fed  on  whole 
milk.    One  pound  of  milk  solids,  practically  all  digesti- 
ble, produced  one  pound  increase  of  live  weight,  which 
was  equivalent  to  a  storage  of  at  least  one-third  pound 
of  body  dry  substance,  a  food  efficiency  for  growth  prac- 
tically ten  times  that  exhibited  with  animals  somewhat 
mature.    Nearly  70  per  cent  of  the  protein  of  the  food 
was  fixed  in  the  bodies  of  these  calves  and  only  a  small 
proportion  was  broken  down,  conditions  quite  the  reverse 
of  those  which  pertain  to  the  use  of  food  by  well-grown 
steers.   Seventy-two  per  cent  of  the  phosphoric  acid  and 
97  per  cent  of  the  lime  were  retained  for  the  purposes  of 
growth.   Later  experiments  with  calves  fed  on  rations  in 
whole  or  in  part  composed  of  skim-milk,  show  a  deposit 
of  from  26  to  43  per  cent  of  the  protein.   These  results 
illustrate  the  vigor  with  which  a  young  animal  assimi- 
lates food  for  growth.   The  facts  show  the  necessity  of 
feeding  young  animals  on  liberal  quantities  of  constructive 
materials,  viz.,  the  proteins  and  ash  ingredients. 

446.  Influence  of  kind  of  food  on  the  kind  of  growth. — 
During  recent   years   there   has  been  much  discussion 
and  many  experiments  touching  the  influence  of  food 
upon   the   development   of   the   animal   body.     Several 
experimenters,    notably    Sanborn    and    Henry,    in    this 
country,  have  compared  the  growth  of  swine  on  rations 
presenting   extreme   differences,   as,   for   instance,   mid- 
dlings and  blood  against  corn  meal  alone,  or  shorts  and 


348  THE  FEEDING  OF  ANIMALS 

bran  against  potatoes,  tallow,  and  corn  meal.  As  would 
be  expected,  the  development  of  the  two  lots  of  pigs  was 
in  these  cases  greatly  unlike.  Those  fed  on  the  nitrog- 
enous rations  contained  more  blood  than  the  other; 
their  organs,  such  as  the  kidneys  and  liver,  were  much 
larger  in  proportion  to  the  weight  of  the  body,  the  bones 
were  stronger,  and  the  proportion  of  muscle  in  the  car- 
cass was  much  greater.  The  differences  were  very  marked. 
It  should  not  be  forgotten,  however,  that  these  were 
extreme  and  somewhat  unusual  rations.  It  is  doubtful 
whether  there  are  generally  sufficient  differences  in  the 
food  combinations  of  ordinary  practice  to  occasion  such 
marked  differences  of  body  structure. 

At  the  Cornell  University  Experiment  Station  lambs 
fed  on  oil  meal  and  bran  made  a  much  more  satisfac- 
tory gain  than  did  those  the  grain  ration  of  which  was 
corn  meal  alone,  but  the  photographs  of  the  carcasses  do 
not  show  a  larger  proportionate  growth  of  muscular  tissue 
from  the  nitrogenous  foods. 

An  elaborate  study  of  the  influence  of  the  ration 
upon  the  composition  of  the  carcass  was  made  at  the 
Maine  Experiment  Station,  where  two  lots  of  steers 
were  fed  from  calfhood  on  rations  widely  unlike  in  their 
nutritive  ratio.  The  hay  fed  was  the  same  for  both  lots. 
The  grain  food  of  one  lot  was  oil  meal,  wheat  bran,  and 
corn  meal,  and  of  the  other  lot  corn  meal,  mixed  with  a 
minimum  proportion  of  wheat  bran,  the  nutritive  ratios 
being  respectively  1 :  5.2  and  1 :  9.7.  One  animal  from  each 
lot  was  killed  at  the  end  of  seventeen  months  of  feeding 
and  the  others  at  the  end  of  twenty-seven  months,  the 
entire  bodies  of  the  four  steers,  exclusive  of  the  skins, 
being  analyzed.  It  was  found  that  the  composition  of 
the  animals  did  not  differ  materially.  (See  Table  LXXV.) 


FEEDING   GROWING  ANIMALS 


349 


TABLE   LXXV. 


PERCENTAGE  COMPOSITION  OF  TOTAL  DRESSED 
CARCASSES  OF  THE  STEERS 


In  fresh  substance 

In  water-free 
substance 

J3 

Water 

c 

d 

'% 

£ 

1 

AH 

& 

< 

Protein,  rich  food  — 
Steer  No.  1  
Steer  No.  2  

17 

27 

27 
17 

Per 
cent 
59.02 
51.91 

52.16 
56.30 

Per 
cent 
17.89 
16.93 

17.10 
17.82 

Per 
cent 
18.53 
25.86 

25.32 
20.27 

Per 
cent 
4.56 
5.30 

5.42 
5.61 

Per 

cent 
43.66 
35.20 

35.75 

40.77 

Per 
cent 
45.23 
53.78 

52.90 
46.39 

Per 
cent 
11.11 
11.02 

11.35 
12.84 

Protein,  poor  food  — 
Steer  No.  3  
Steer  No.  4  

The  amount  of  growth  was  at  first  more  rapid  with 
the  more  nitrogenous  ration,  but  the  kind  of  growth 
appeared  to  have  been  controlled  by  the  somewhat  fixed 
constitutional  habits  of  the  breed.  Nevertheless,  the 
evidence  of  all  well-conducted  experiments  and  of  all 
experience  is  unanimous  in  emphasizing  the  necessity  of 
supplying  in  the  food  of  young  animals  an  abundance  of 
those  nutrients  which  are  needed  for  the  building  of 
bone  and  muscle.  A  satisfactory  development  of  the 
organism  at  maturity  is  insured  only  when  the  early 
growth  is  liberal  and  uniform,  and  is  such  as  to  produce 
strong  bone  and  a  vigorous  muscular  system.  More 
than  this,  there  is  induced  by  proper  nourishment  a 
lively  temperament  of  energy  of  body,  which  chemical 
analysis  cannot  search  out  or  measure,  but  which  gives 
the  chief  value  to  certain  classes  of  animals  and  is  desira- 
ble in  all.  It  is  believed  that  this  condition  of  strong 
vitality  is  promoted  by  a  liberal  supply  of  the  proteins 
in  the  food. 

447.  Estimated  energy  requirements  for  one  pound 
of  gain  in  weight  by  growing  cattle  and  sheep. — Armsby 


350 


THE  FEEDING  OF  ANIMALS 


has  made  estimates  of  the  requirements  for  each  pound  of 
growth  of  cattle  and  sheep  at  different  ages,  for  which  he 
does  not  claim  any  high  degree  of  accuracy.* 

TABLE  LXXVI 


Age 

Energy  value 

Months 

3      .    .    .    .  ..--.    .,.    -....•>.-  .  ...  • 
6     .    .-'.    .    .    .    .    .   ...    ....  !•;    .    .       .' 

Therms 
1.5 

1  7 

12    'i  -..'  '•': 
is      /  .  .-  .'....  .  ".  '/••.  •  -  .     $  i\  '  .  ' 

2. 
2  5 

24 

2.75 

30     .    .. 

3. 

This  would  indicate  that  for  an  animal  of  the  age  of 
three  months  a  pound  of  growth  would  require  an  addi- 
tion to  the  ration  of  two  and  one-fourth  pounds  of  oats, 
and  at  the  age  of  thirty  months  four  and  one-half  pounds. 

The  same  author  gives  estimated  requirements  a 
day  and  head  for  growing  cattle,  these  to  include  the 
maintenance  requirement  :* 

TABLE  LXXVII 


Age 

Live 
weight 

Digestible 
protein 

Energy 
value 

Months 

3 

Pounds 

275 

Pounds 
1  1 

Therms 

5. 

6 

425 

1.3 

6. 

12    ... 

650 

1.65 

7. 

18    

850 

1.7 

7.5 

24 

1,000 

1.75 

8. 

30    

1,100 

1.65 

8. 

In  order  to  give  concrete  expression  to  the  standard 
that  applies  to  a  growing  animal  one  year  old,  weighing 
650  pounds,  there  has  been  calculated  the  necessary  ration : 

*  Based  on  true  protein  and  production  values. 


FEEDING  GROWING   ANIMALS  351 

Pounds 

Clover  hay 10 

Wheat  middlings 3 

Linseed  meal 2 

448.  Milk   for   young   animals. — In   considering   the 
feeding  of  very  young  animals,  we  recognize  the  mother's 
milk  as  in  general  supplying  the  necessary  nutrients  in 
the  best  forms  and  proportions.   It  is  true  in  the  case  of 
cows  that  the  very  rich  milk  of  the  butter  breeds,  when 
generously  fed,  often  causes  a  serious  disturbance  of  the 
calf's  digestive  organs,  but  the  fact  remains  that  casein, 
milk-fat,  and  milk-sugar  are  adapted  through  Nature's 
design  to  the  digestive  processes  and  the  nutrition  of 
young  animals.    Moreover,  milk  is  rich  in  the  mineral 
compounds  needed  for  bone  formation.    When,  there- 
fore, it  becomes  necessary  or  desirable  to  substitute  other 
food  for  the  mother's  milk,  it  is  essential  not  to  act 
counter  to  physiological  necessities  and  conditions. 

One  fact  of  importance  is  that  the  very  young  ani- 
mal is  somewhat  undeveloped  in  its  capacity  to  digest 
the  starchy  grains  and  similar  substances,  the  secre- 
tions necessary  for  this  purpose  not  yet  being  abundant. 
It  follows,  then,  that  the  first  substitute  for  whole  milk 
should  not  consist  largely  of  the  insoluble  carbohydrates. 
Again,  the  young  animal's  stomach  is  at  first  unfitted  for 
receiving  and  utilizing  bulky,  fibrous  food.  Some  time 
must  elapse  before  the  calf  or  colt  can  secure  much 
nourishment  from  grass,  hay,  or  like  materials. 

THE    FEEDING   OF  CALVES 

449.  Skimmed  milk  as  a  substitute  for  whole  milk 
in  feeding  calves. — The  most  successful  way  of  feeding 


352  THE  FEEDING  OF  ANIMALS 

calves  to  secure  rapid  growth,  especially  to  produce  veal 
of  the  highest  quality,  is  to  supply  them  with  whole  milk 
up  to  the  limit  of  their  capacity  when  this  can  be  done  with 
safety.  Where  they  are  to  be  raised  for  stock  purposes, 
satisfactory  growth  may  be  maintained  with  the  use  of 
substitutes  for  whole  milk,  which  is  fortunate,  because 
with  the  exception  of  the  western  plains,  where  cows  are 
cheaply  kept  simply  for  breeding  purposes,  or  where  a 
breeder  is  selling  his  increase  at  fancy  prices,  the  feeding 
of  whole  milk  is  not  warranted  by  the  value  of  the  result- 
ing animal. 

For  this  reason  most  dairymen,  particularly  those 
who  sell  milk  as  such,  kill  the  calves  at  the  age  of  a  few 
days,  excepting,  perhaps,  during  that  portion  of  the  year 
when  veal  sells  at  a  very  high  price.  On  the  other  hand, 
many  dairymen  who  have  a  supply  of  skimmed  milk 
successfully  feed  this  to  growing  calves,  when  it  is  desired 
to  raise  heifers  or  even  steers.  Experience  has  shown 
that  it  is  entirely  practical  to  do  this,  and  it  is  certainly 
economical,  for  experiments  have  demonstrated  that,  as 
prices  average,  the  cost  of  a  pound  of  growth  so  produced 
is  at  least  not  over  one-third  what  it  would  be  if  whole 
milk  were  fed. 

As  a  guide  in  providing  a  substitute  for  whole  milk, 
it  may  be  stated  that  a  vigorous  calf  should  very  early 
be  made  to  eat  daily  not  less  than  three  pounds  of  highly 
digestible  matter  with  a  nutritive  ratio  at  first  not  wider 
than  that  of  whole  milk  solids.  The  exclusive  feeding  of 
skimmed  milk  for  any  length  of  tune  is  not  to  be  recom- 
mended. Experience  shows  that  for  young  calves  it 
should  be^so  combined  with  other  materials  that  a  mix- 
ture is  obtained  which,  so  far  as  possible,  resembles 
whole  milk  in  its  nutritive  ratio.  After  the  fat  is  removed 


FEEDING  GROWING  ANIMALS  353 

from  the  milk,  the  non-nitrogenous  compounds  are 
probably  not  present  in  sufficient  proportion  to  protect 
the  protein  from  waste  as  fuel.  No  feeding-stuff  appears 
to  be  a  more  efficient  amendment  of  skimmed  milk  for 
the  earliest  feeding  than  flaxseed  meal  cooked  into  a 
porridge.  The  explanation  of  this  is  the  high  percentage 
of  oil  in  this  meal,  its  low  content  of  starch,  and  its  high 
rate  of  digestibility.  Besides,  it  appears  to  promote  a 
healthy  condition  of  the  organs  of  digestion.  Oil  meal 
may  be  used  in  its  stead,  but  it  is  less  desirable  at  first. 
The  calf  should  be  allowed  whole  milk  for  a  few 
days,  not  necessarily  more  than  a  week,  when  it  may 
be  gradually  changed  over  to  skimmed  milk  and  flax- 
seed  meal.  An  admirable  mixture  is  prepared  by  cook- 
ing the  flaxseed  meal  in  water  in  the  proportion  of  one 
to  six  by  volume,  and  adding  a  small  amount  of  this 
(the  equivalent  of  three  or  four  tablespoonfuls  of  the 
dry  meal  at  first)  to  eighteen  or  twenty  pounds  of  warm 
skimmed  milk,  which  may  serve  as  a  day's  ration.  The 
quantity  of  meal  should  be  gradually  increased  up  to  one 
pound  a  day  inside  of  a  few  weeks.  In  six  or  eight  weeks 
the  calf  should  be  allowed  access  to  dry  oatmeal,  or  oat- 
meal and  wheat  middlings,  or  the  oatmeal  and  middlings 
may  be  boiled  with  the  flaxseed  meal  and  mixed  with  the 
milk.  After  ninety  days  the  flaxseed  meal  may  be  dropped 
for  the  sake  of  economy.  The  calf  will  soon  appreciate 
a  wisp  of  early  cut  hay,  some  coarse  food  becoming 
a  necessity  before  many  months  pass.  This  method 
of  feeding  has  repeatedly  produced  rapid  growth  and 
fine  animals.  For  heifers  it  is  probably  to  be  preferred 
to  whole-milk  feeding,  as  it  is  fully  as  conducive  to  the 
vigorous  development  of  the  muscular  system  and  is  less 
likely,  perhaps,  to  promote  a  tendency  to  lay  on  body  fat. 
w 


354  THE  FEEDING   OF  ANIMALS 

450.  Calf  rations  without  milk  products. — An  exam- 
ination of  the  results  of  much  experimental  work  shows 
very  clearly  that  strong,  healthy  calves  can  be  raised 
without  skimmed  milk  or  even  milk  of  any  kind  after  a 
brief  period,  although  the  rate  of  gain  may  not  be  so 
rapid  as  when  whole  milk  or  skimmed  milk  is  available 
for  at  least  part  of  the  ration.    In  these  experiments, 
where  careful  records  have  been  made,  mixtures  of  oat- 
meal and  other  cereal  products  with  linseed  meal,  thor- 
oughly cooked,   may  be  used   to  produce   satisfactory 
growth,  even  if  growth  is  not  so  rapid  as  with  milk  prod- 
ucts.  This  appears  to  be  no  disadvantage  in  the  subse- 
quent development  of  the  animal.     Even  if  skimmed 
milk  is  available,  cereal  products  and  the  oil-meal  prod- 
ucts make  desirable  amendments  to  the  milk. 

The  Dairy  Division  of  the  United  States  Department 
of  Agriculture,  in  experiments  with  twenty-two  animals, 
has  showed  that  calves  make  as  rapid  gain  upon  sour 
skimmed  milk  as  upon  sweet  skimmed  milk,  other  experi- 
ments indicating  that  whey  may  be  used  as  a  substitute  for 
skimmed  milk,  provided  proper  foods  are  combined  with  it. 

Hay  tea  is  sometimes  used  as  a  milk  substitute,  but 
it  is  a  poor  one.  Only  a  small  proportion  of  the  nutrients 
of  hay  is  soluble,  and  the  water-extract  is  a  dilute  and 
comparatively  innutritious  food  for  a  growing  animal, 
the  use  of  which  can  be  justified  only  in  the  absence  of 
milk  in  any  form,  and  which,  when  used,  must  be  very 
liberally  fortified  by  grain  feeds. 

THE   FEEDING   OF  LAMBS 

451.  Feeding  ewes  with  lamb. — The  first  growth  of 
lambs  is  chiefly  from  the  mother's  milk  and  we  have  little 


FEEDING  GROWING  ANIMALS  355 

occasion  to  consider  substitutes  for  this  food.  The  fact 
first  in  order  and  most  important  in  this  connection  is 
that  well-fed  mothers  are  absolutely  essential  to  rapid 
growth.  A  lamb  must  be  fed  through  its  dam.  Nothing 
is  more  pitiable  than  the  sight  of  a  pair  of  hungry  twin 
lambs  making  an  effort  to  satisfy  their  insistent  demands 
for  growth  with  the  milk  furnished  by  a  small,  lean, 
under-fed  mother.  The  treatment  of  the  ewe  before 
the  birth  of  her  young  should  be  such  as  to  prepare  her 
for  the  strain  of  supplying  a  generous  flow  of  milk. 

Ewes  that  are  suckling  lambs,  while  fed  from  the  barn, 
should  be  supplied  with  good  clover  or  alfalfa  hay,  or  hay 
from  fine  mixed  grasses.  Pea  and  bean  straws  are  excel- 
lent coarse  feeds  for  sheep.  Timothy  hay  is  an  abomina- 
tion as  sheep  food,  especially  under  these  conditions. 
The  grain  ration  should  not  be  less  than  three-fourths 
of  a  pound  daily,  made  up  in  part  of  one  or  more  of  the 
highly  nitrogenous  feeding-stuffs.  It  is  also  desirable  to 
feed  a  small  proportion  of  some  succulent  food.  What  is 
needed  is  a  milk-producing  ration,  and  the  discussion  of 
feeding  cows  for  milk  production  in  a  preceding  chapter 
is  in  part  pertinent  to  ewes.  Corn,  oats,  wheat  bran  or 
middlings,  beans,  peas,  gluten  and  oil  meals  are  all  useful 
in  making  up  such  a  ration.  With  safe  feeding,  one  pound 
daily  of  a  mixture  of  oil  or  gluten  meal  one  part,  wheat 
bran  two  parts,  and  corn  meal  two  parts,  combined  with 
two  or  three  pounds  of  roots  or  silage  and  what  coarse 
feed  the  appetitite  will  bear,  is  a  good  milk  ration,  and 
will  bring  the  ewes  through  the  strain  of  suckling  lambs 
in  good  condition. 

452.  Grain  foods  accessible  to  lambs. — If  it  is  desired 
to  produce  the  most  rapid  growth  of  the  lambs,  they 
should  also  have  access  from  nearly  the  first  to  a  grain 


356  THE  FEEDING  OF  ANIMALS 

mixture.  Experiments  indicate  that  this  mixture  is  most 
economical,  especially  if  the  lambs  are  to  be  fed  later  for 
the  market,  when  containing  a  generous  proportion  of 
corn  meal,  to  which  may  be  added,  among  other  mate- 
rials, ground  oats,  wheat  bran,  gluten  feed  or  meal,  or  oil 
meal,  reference  being  had  to  the  ruling  market  prices. 
In  an  experiment  at  the  Maine  Experiment  Station, 
lambs  suckled  by  grain-fed  mothers  and  with  access  to 
grain  themselves  made  75  per  cent  or  more  gain  in  live 
weight  than  those  did  that  received  no  grain  and  which 
were  suckled  by  mothers  that  ate  a  limited  grain  ration. 
Five  and  three-fourths  pounds  of  grain  produced  one 
pound  of  growth.  At  the  Wisconsin  Experiment  Station, 
as  an  average  of  three  trials,  lambs  fed  grain  before  wean- 
ing gained  in  ten  to  twelve  weeks  seven  and  a  half 
pounds  more  each  than  those  not  so  fed.  Four  pounds 
of  grain  produced  one  pound  of  live  weight. 

Liberal  feeding  means  more  economical  growth,  a 
higher  quality  of  product,  and  the  earliest  possible  mar- 
ket. The  foregoing  discussion  is  applicable  to  the  rais- 
ing of  early  lambs.  If,  however,  they  are  dropped  dur- 
ing the  grazing  season  where  the  ewes  have  abundant 
pasturage,  the  question  of  feeding  is  simplified,  for  no 
ration  is  more  promotive  of  abundant  milk  secretion 
than  young  grass;  besides,  the  low  price  at  which  late 
lambs  are  usually  sold  does  not  encourage  extensive  grain 
feeding.  When  lambs  are  grown  for  breeding  stock  their 
early  grain  rations  should  be  lighter,  and  may  properly 
consist  more  largely  of  oats  and  bran,  with  a  smaller 
proportion  of  corn. 

453.  Standards  for  growing  sheep. — For  growing 
sheep  beyond  the  age  of  six  months,  Armsby  has  offered  the 
following  standards,  based  on  Kellner's  production  values : 


FEEDING   GROWING  ANIMALS 


357 


TABLE  LXXVIII.    ESTIMATED  REQUIREMENTS  PER  DAY  AND 
HEAD  FOR  GROWING  SHEEP 


Age 

Live  weight 

Digestible 
protein 

Energy 
value 

Months 

Pounds 

Pounds 

Therms 

6    

70 

SO 

1  SO 

9    

90 

.25 

1.40 

12    

110 

.23 

1.40 

15    .............. 

130 

.23 

1.50 

18    

145 

.22 

1.60 

Expressed  in  terms  of  an  actual  ration  a  bunch  of  ten 
growing  lambs  nine  months  old  would  require  on  the 
basis  of  the  foregoing  standard  the  following  quantities: 

RATION  FOR  TEN  LAMBS,  900  POUNDS.    AGE  NINE  MONTHS 

Pounds 

Clover  hay      20 

Turnips 20 

Peas 4 

Linseed  meal      2 


FEEDING  COLTS 

454.  Food  as  related  to  quality  of  the  horse. — The 
value  of  a  horse  for  either  draft  or  road  purposes  is  greatly 
dependent  upon  those  physical  qualities  which  secure 
vigor  and  endurance.  A  horse  is  not  regarded  as  desira- 
ble that  is  devoid  of  "nerve"  and  that  cannot  sustain, 
if  necessary,  the  strain  of  hard,  or  even  severe,  work; 
and  breeders  seek  to  produce  animals  having  these  char- 
acteristics. Two  main  factors  are  involved  in  the  proper 
physical  development  of  the  colt:  food  and  exercise.  The 
latter  is  a  part  of  the  general  management  to  which  the 
horse-breeder  must  give  detailed  attention  and  will  not 
be  discussed  in  this  connection.  The  technics  with  which 


358  THE  FEEDING  OF  ANIMALS 

the  horseman  should  be  familiar  must  be  learned  through 
experience  and  by  consulting  special  literature. 

It  is  proper  to  state  that  our  knowledge  concerning 
the  feeding  of  colts  consists  largely  of  the  conclusions 
derived  from  experience  of  practical  men.  Very  little 
experimental  attention  has  been  given  to  this  subject 
by  investigators.  During  the  years  that  experiment 
stations  have  existed  in  the  United  States  few  stations 
have  reported  experiments  along  this  line,  and  these  were 
not  extensive;  but  notwithstanding  the  lack  of  direct 
data  from  scientific  sources  there  are  well-proven  and 
safe  facts  to  which  we  can  refer. 

455.  Feeding  the  colt  through  the  dam. — The  proper 
feeding  of  the  young  foal  is  accomplished  first  through 
the  proper  feeding  of  the  dam.  The  mare  with  a  colt  at 
her  side  should  be  regarded  as  a  milch  animal,  making 
demands  upon  the  food  for  generous  milk  production 
similar  to  those  made  by  the  milch  cow.  This  is  equiva- 
lent to  the  statement  that  when  suckling  her  foal  the  dam 
should  be  given  foods  that  stimulate  milk  secretion.  If 
she  is  allowed  the  run  of  a  good  pasture,  both  mother  and 
colt  will  usually  thrive  satisfactorily.  Young  pasture 
grass  is  as  efficient  with  the  mare  as  with  the  cow.  If,  on 
the  other  hand,  the  feeding  is  from  the  stable,  either 
wholly  or  to  amend  an  insufficient  or  inferior  food-supply 
from  grazing,  then  the  grain  ration  should  be  made  to 
include  such  feeding-stuffs  as  barley,  oats,  wheat,  wheat 
bran,  wheat  middlings,  peas,  and  even  a  small  propor- 
tion of  linseed  meal.  Whenever  soiling-crops  are  grown 
these  may  be  fed,  especially  alfalfa.  In  case  the  legume 
fodders  are  available,  either  green  or  dried,  the  necessity 
for  protein  in  the  grain  is  not  so  great  and  corn  may 
form  a  larger  proportion  of  the  ration. 


FEEDING  GROWING  ANIMALS  359 

A  good  grain  mixture  for  ordinary  conditions  would 
be  cracked  corn  two  parts,  wheat  bran  seven  parts,  and 
linseed  meal  one  part;  or  ground  oats  four  parts,  wheat 
middlings  five  parts,  and  linseed  meal  one  part. 

456.  Rations  for  the  colt  before  weaning. — Before  the 
colt  is  weaned,  with  good  management,  he  will  learn  to 
eat  grain  which  is  very  likely  to  be  the  same  mixture  as 
that  eaten  by  the  dam.    If  desired,  an  enclosure  may  be 
built,  into  which  the  colt  and  not  the  mother  can  pass, 
where  a  special  grain  food  may  be  provided.   This  brings 
us  to  the  consideration  of  what  shall  be  the  grain  ration 
of  the  colt,  both  before  and  after  weaning. 

457.  Oats  as  horse  feed. — The  opinion  is  generally 
held  that  oats  are  superior  to  all  other  feeding-stuffs  as 
horse  food,  particularly  for  the  development  of  those 
qualities  of  temperament  and  muscle  which  are  regarded 
as  so  desirable,  especially  in  a  carriage  horse.    Oats  are 
usually  comparatively  costly,  but  it  is  claimed  that  the 
superior  results,  whether  in  the  kind  of  development  of 
the  colt  or  in  the  quality  of  service  of  the  mature  animal, 
justify  their  use.    In  this  particular  case,  as  in  others, 
certain  statements  are  currently  accepted  as  facts  which 
have  no  well-established  basis. 

Reference  is  frequently  made  to  the  tonic  effect  of 
oats,  and  there  has  existed  a  popular  notion  that  this 
grain  contains  a  peculiar  compound  which  acts  as  a  nerve 
stimulant  and  imparts  "life"  to  the  horse. 

It  was  announced  in  1883  that  Sanson  had  discovered 
in  oats  a  characteristic  alkaloid  having  a  stimulating 
effect  upon  the  motor  nerves  of  the  horse,  but  subse- 
quent elaborate  investigations  by  Wrampelmyer  failed  to 
verify  Sanson's  conclusions.  Notwithstanding  the  fact 
that  the  oat  kernel  has  been  the  subject  of  very  care- 


360  THE  FEEDING  OF  ANIMALS 

ful  chemical  studies,  it  is  not  found  that  it  contains  any 
compounds  so  characteristically  unlike  those  of  other 
grains  as  to  account  for  an  unusual  influence  upon  the 
nervous  system,  or  for  a  superior  development  of  the 
muscles. 

It  may  be  suggested  that  the  "life,"  or  nervous  con- 
dition, of  a  horse  is  a  resultant  of  several  factors  or 
influences.  These  are  the  quantity  of  digestible  food  sup- 
plied, the  proportion  of  protein  in  the  ration,  the  con- 
dition of  the  digestive  tract,  care,  exercise,  and  all  the 
many  small  influences  which  affect  health.  In  those 
instances  where  feeding  oats  has  seemed  to  improve  the 
performance  of  the  horse,  even  if  this  has  actually 
occurred,  we  have  no  assurance  that  in  changing  the 
ration  the  amount  and  proportions  of  the  nutrients 
digested  have  remained  the  same.  It  seems  entirely 
probable  that  if  thorough  comparison  could  be  made 
between  oats  and  the  best  grain  mixtures  which  could 
be  suggested  in  the  light  of  present  knowledge,  the  oats 
would  not  maintain  so  great  a  superiority  over  other 
feeds  for  growing  colts  as  is  now  generally  attributed  to 
them.  Experiments  which  have  been  made  indicate  that 
for  producing  rapid  growth  oats  were  inferior  to  either  a 
mixture  of  peas  and  middlings,  or  to  a  mixture  of  mid- 
dlings, gluten  meal,  and  linseed  meal;  but  these  obser- 
vations were  not  carried  far  enough  to  determine  the 
relative  effect  upon  the  quality  of  the  animal. 

458.  Rations  for  growing  colts. — Doubtless  all  neces- 
sary conditions  for  producing  growth  and  quality  in  colts 
can  be  met  by  a  ration  of  which  oats  form  a  part.  The 
following  grain  mixtures  are  suggested  as  illustrative  of 
good  ones: 


FEEDING  GROWING  ANIMALS  361 

Mixture  1  Mixture  2 


Oats     ; 

Parts 
.    .      4 

Corn    . 

Parts 
2 

Bran  or  middlings 
Peas 

.    .      4 
2 

Oats     .    .    .  .;,'  . 
Bran         •  ' 

.    .    .    .      4 
3 

Oil  meal  . 

1 

These  mixtures  are  generally  less  expensive  than  oats 
alone,  and  in  kind  fully  meet  the  demands  for  growth 
of  both  bone  and  muscle. 

Henry  gives  as  a  fab*  allowance  of  grain  for  a  colt, 
measured  in  oats,  the  following  quantities:  Up  to  one 
year  of  age,  two  to  three  pounds;  from  one  to  two  years, 
four  to  five  pounds;  from  two  to  three  years,  seven  to 
eight  pounds.  In  using  the  other  grain  feeds  suggested, 
which  mostly  have  a  higher  rate  of  digestibility  than  oats, 
no  larger  quantities  would  be  necessary.  Skim-milk  may 
be  fed  to  colts  in  limited  amounts  with  good  results,  as 
experiments  show.  Feeding  it  in  quantities  sufficient  to 
force  very  rapid  growth  is  not  wise. 

It  is  generally  conceded  that  the  colt  should  be  allowed 
to  eat  a  reasonable  proportion  of  coarse  feed  as  a  means  of 
properly  developing  the  digestive  tract.  It  is  entirely  pos- 
sible to  supply  concentrated  grains  too  freely,  to  the 
exclusion  of  more  bulky  materials,  and  in  that  way  fail 
to  secure  a  desirable  distension  of  the  alimentary  canal. 
This  does  not  mean  that  the  colt  should  be  allowed  to 
gorge  himself  with  hay  or  other  coarse  material,  as  an 
unfortunate  extreme  in  this  direction  is  easily  reached. 


CHAPTER  XXI 

FEEDING  ANIMALS  FOR  THE  PRODUCTION  OF 
MEAT 

THE  production  of  beef  was  at  one  time  a  source 
of  income  to  nearly  all  farms.  In  earlier  days  the  New 
England  farmer  annually  sent  to  the  market  a  few  fat 
steers  or  oxen.  The  beef  consumed  in  the  United  States 
and  that  exported  now  comes  very  largely  from  the  wide 
grazing  areas  of  the  West,  where  the  cost  of  feed  and  the 
necessary  amount  of  labor  are  at  a  minimum.  The 
reasons  for  this  change  are  not  hard  to  find.  The  food 
cost  of  beef-making  is  relatively  large  as  compared  with 
dairy  products,  and  in  the  East  the  growth  of  home 
markets  for  milk  and  cream  has  made  it  possible  for 
farmers  to  turn  their  high-cost  feeding-stuff  into  prod- 
ucts having  a  higher  proportionate  market  price  than 
beef.  Moreover,  certain  eastern  lands  have,  with  enlarg- 
ing markets,  been  occupied  to  good  advantage  with  fruit 
and  vegetables.  The  time  has  come,  now  that  the  wide 
areas  of  the  West  are  more  densely  peopled,  when  beef 
production  is  receiving  more  attention  in  the  eastern 
states.  Some  eastern  farmers  appear  now  to  find  it  profita- 
ble. It  is  certain  that  it  involves  good  judgment,  skill, 
and  the  art  of  feeding  to  the  highest  degree,  especially  if 
fair  returns  are  to  be  secured.  The  breeding  or  selection 
of  animals  of  the  most  profitable  type  that  will  supply 
the  market  with  a  high-grade  product,  and  stable  feed- 
ing, so  as  to  produce  rapid  and  continuous  increase, 

(362) 


FEEDING  FOR  MEAT 


363 


requires  experience  and  an  intelligent  application  of  all 
the  factors  involved. 


BEEF  PRODUCTION 

459.  Nature  of  the  growth  with  beef  production.— 
Feeding  steers  or  oxen  for  the  market  may  be  carried 
on  with  young  animals  that  are  still  making  some  growth 
of  bone  and  muscle,  or  with  those  so  mature  that  addi- 
tional weight  comes  almost  wholly  from  a  deposition  of 
fat  in  the  tissues  already  formed.  This  is  the  difference 
between  feeding  a  two-year-old  and  a  five-year-old  steer. 
In  either  case  the  predominating  constituent  of  the 
increase  is  fat.  This  fact  is  established  by  the  investi- 
gation of  Lawes  and  Gilbert  and  by  one  experiment  in 
this  country.  Gilbert,  in  his  lectures  summarizing  the 
Rothamsted  work,  gave  the  following  figures: 

TABLE  LXXIX.     COMPOSITION  OF  INCREASE  WHEN  STEERS  ARE 
FATTENING 


Water 

Ash 

Protein 

Fat 

Oxen  fattened  very  young               .    .    . 

Percent 

32-37 
25-30 

42.4 

Percent 

2M 

*H 

6. 

Percent 

10 

7-8 

14.1 

Percent 

50-55 
60-65 

37.5 

Matured  animals,  final  period     .... 
American  results  with  well-fed  steers, 
growth  from  17  months  to  27  months 
of  age                                            .    .    . 

These  figures  may  be  regarded  as  reliable,  and  they 
show  most  conclusively  that  in  beef  production  the 
constructive  use  of  the  food  is  largely  hi  the  direction 
of  fat-forming. 

460.  Rate  of  increase  of  fattening  animals. — The 
extent  of  the  actual  production  which  occurs  can  be 


364  THE  FEEDING  OF  ANIMALS 

closely  estimated  for  any  given  case.  It  is  considered 
satisfactory  if  the  rate  of  increase  during  a  reasonably 
long  period  of  fattening  is  2  pounds  live  weight  a  day. 
This  means  the  actual  addition  to  the  dry  substance  of 
the  body  of  from  1.3  to  1.5  pounds.  Sometimes  during 
short  periods  with  excessive  feeding  the  daily  gain  may 
be  3  pounds  live  weight,  and  generally  after  animals  are 
well  fattened,  during  the  finishing  period,  it  may  be  as 
low  as  1  pound  or  less.  The  actual  daily  growth  of  new 
material  may  vary  then,  aside  from  the  water,  from  .6  to 
2.25  pounds  a  day.  Actual  fat  formation  may  thus 
range  from  A  to  1.8  pounds  a  day.  The  protein-con- 
tent of  the  increase,  on  the  other  hand,  probably  does 
not  exceed  .3  pound  daily  in  any  instance,  and  with 
mature  animals  it  is  very  insignificant. 

461.  The  food  needs  of  the  fattening  steer. — In  view 
of  the  foregoing  facts  and  of  the  conclusion  as  to  the  fat- 
forming  function  of  carbohydrates,  it  is  clear  that  the 
non-protein  part  of  the  ration  may  be  the  source  of  the 
chief  part  of  the  body  substance  laid  on  by  a  fattening 
steer.  The  amount  of  protein  necessary  for  constructive 
work  seems  to  be  very  small — with  mature  animals  it  is 
practically  nothing.  It  would  seem,  then,  looking  at  the 
matter  merely  from  the  standpoint  of  the  demands  for 
growth,  that  in  feeding  fairly  mature  animals  for  beef 
production  a  ration  may  be  efficient  with  a  wide  nutritive 
ratio,  much  wider  than  was  recommended  in  the  Ger- 
man standards. 

It  is  recognized,  though,  that  we  cannot  decide  upon 
a  ration  merely  upon  the  basis  of  the  raw  materials  that 
are  needed  for  constructive  purposes.  The  influence  of  a 
particular  feed  or  of  a  variety  of  feeds  on  the  appetite 
and  on  what  we  speak  of  as  general  condition,  as 


FEEDING  FOR  MEAT  365 

well  as  upon  the  quality  of  the  product,  and  the  necessity 
of  avoiding  so  large  a  preponderance  of  carbohydrates 
as  to  cause  a  possible  depression  of  digestibility,  are  all 
points  which  must  be  considered  in  determining  the  value 
of  a  ration.  We  should  remember,  also,  that  the  stimulat- 
ing effect  of  the  food  upon  the  vital  functions  is  a  factor 
in  successful  feeding.  So,  after  all,  we  must  appeal  to 
experience,  scientific  and  practical,  for  information  as  to 
what  rations  are  efficient  for  fattening  purposes. 

The  German  standard  rations  for  fattening  bovines 
which  were  recommended  called  for  18  to  18.4  pounds  of 
digestible  organic  matter  daily  for  each  1,000  pounds  of 
live  weight,  with  a  ratio  of  1 :  5.4  to  1 :  6.5,  requiring  from 
2.5  to  3  pounds  of  a  digestible  protein.  In  view  of  more 
recent  scientific  conclusions  concerning  the  functions  of 
nutrients,  it  is  not  easy  to  understand  why  a  fattening 
steer  requires  more  protein  than  a  milch  cow  or  even 
as  much. 

462.  Scientific  experiments  with  fattening  animals. — 
Feeding  experiments  with  fattening  oxen,  conducted 
under  the  improved  methods  of  research,  give  results 
not  inconsistent  with  the  facts  to  which  attention  has 
been  called.  Kellner  made  a  large  number  of  experi- 
ments with  fattening  animals  by  the  aid  of  the  respiration 
apparatus,  and  he  concluded  that  the  nutritive  ratio  of 
a  fattening-ration  may  vary  from  1:4  to  1 : 10  without 
affecting  the  increase  of  body  substance  from  a  unit  of 
digestible  food  material,  provided,  however,  that  the 
nutrients  supplied  above  maintenance  needs  shall  come 
from  the  more  easily  digestible  feeding-stuffs.  He  cites, 
in  the  support  of  his  conclusion,  the  outcome  of  nineteen 
previous  experiments  by  Wolff,  in  which  rations  varying 
in  nutritive  ratio  from  1:4  to  1 : 9.5  showed  no  material 


366  THE  FEEDING  OF  ANIMALS 

differences  in  the  efficiency  of  a  unit  of  digestible  matter. 
It  seems  to  be  agreed  that  a  wide  nutritive  ratio  is  not 
inconsistent  with  most  successful  feeding  of  fattening 
steers,  especially  those  that  are  mature.  If  the  animals 
are  so  young  as  to  be  making  material  growth,  there  is 
more  reason  for  avoiding  a  very  wide  ratio. 

463.  Practical  feeding  experiments  in  fattening  ani- 
mals.— Among  the  practical  feeding  experiments  con- 
ducted in  the  United  States,  there  are  several  instances 
where  the  wide-ratio  rations  have  been  found  equal  to 
the  more  nitrogenous.  On  the  other  hand,  and  perhaps 
in  a  majority  of  experiments,  the  rations  containing  the 
largest  proportion  of  protein  have  caused  the  most  rapid 
growth.  In  1893  the  writer  made  a  careful  study  of  many 
previous  experiments  and  found  that  the  addition  of  some 
highly  nitrogenous  feeding-stuff  to  corn  meal,  or  other 
home-raised  grain,  in  most  instances  increased  the  pro- 
ductive value  of  the  ration.  This  fact  stands  in  apparent 
conflict  with  the  more  scientific  conclusions  to  which 
reference  has  been  made.  The  probable  explanation  of 
this  discrepancy  is  that  the  rations  richest  in  protein 
have  generally  contained  the  greater  variety  of  feeding- 
stuffs,  have  been  more  palatable,  more  stimulating  to 
the  appetite,  and,  in  general,  have  caused  a  more  vigorous 
exercise  of  the  animal's  functions.  The  proportion  of 
protein  has  probably  been  a  minor  factor.  If  as  great  a 
variety  of  as  palatable  and  as  easily  digestible  materials 
can  be  fed  without  the  use  of  highly  nitrogenous  feeding- 
stuffs  as  with  them,  the  result  will  doubtless  be  just  as 
favorable.  This  means  that  a  mixture  of  home-raised 
grains  may  form  as  efficient  a  ration  for  fairly  mature 
fattening  steers  as  when  the  oil  meals  or  gluten  meals 
are  introduced.  Palatableness,  variety,  and  ease  of 


FEEDING  FOR  MEAT  367 

digestion  are  the  main  points  to  be  secured,  and  these 
factors  have  been  somewhat  overshadowed  by  the  effort 
to  secure  merely  a  definite  nutritive  ratio. 

It  need  not  be  feared  that  when  mixed  cereal  grains 
are  fed  as  the  major  part  of  the  ration,  there  will  be 
a  materially  lower  rate  of  digestibility  than  when  a 
protein  food  is  introduced.  There  is  still  something  to 
be  said,  however,  in  favor  of  adding  to  a  fattening-ration 
a  small  proportion  of  an  oil  meal,  or  of  some  material 
of  similar  character,  for  palatableness  is  thus  promoted, 
and  observations  show,  in  many  instances,  that  an 
appearance  of  greater  thrift  and  vigor  is  thus  induced, 
which  is  perhaps  due  to  the  stimulating  effect  of  the 
greater  amount  of  circulatory  protein  upon  the  metabolic 
processes  of  the  animal.  With  young  steers  making  some 
growth  of  bone  and  muscle,  a  small  quantity  of  a  protein 
food  is  of  unquestioned  advantage. 

464.  German  fattening  for  bovines'  ration  excessive. — 
The  German  standard  for  fattening  cattle  is  open  to 
criticism  as  to  the  quantity  of  nutrients  recommended 
for  1,000  pounds  of  live  weight.  In  order  to  supply  18.4 
pounds  of  digestible  organic  matter  it  would  be  neces- 
sary to  feed,  for  instance,  8  pounds  of  hay  and  21.5  pounds 
of  an  ordinary  mixture  of  corn  meal,  bran,  and  oil  meal. 
While  it  may  be  possible  to  induce  young  steers  weigh- 
ing from  600  to  800  pounds  to  eat  at  this  rate  for  a  short 
time,  so  large  a  ration  is  seldom,  if  ever,  so  profitable  as 
a  smaller  one,  even  if  it  could  be  fed  with  safety.  If  an 
attempt  were  made,  however,  to  apply  this  formula  to 
mature  steers  weighing  from  1,300  to  1,500  pounds  the 
situation  would  become  absurd,  because  the  ration  would 
then  be  from  10.5  to  12  pounds  of  hay  and  from  25  to  32 
pounds  of  mixed  grains  for  a  single  animal.  An  appeal 


368  THE  FEEDING  OF  ANIMALS 

to  concrete  examples  of  steer-feeding  will  clearly  show 
the  excessive  requirements  of  the  German  standard  for 
fattening  cattle.  In  1891  to  1893  the  Kansas  Agricul- 
tural Experiment  Station  conducted  feeding  experiments 
with  three-year-old  steers,  and  as  these  are  good  exam- 
ples of  practical  management,  the  data  from  them  will 
serve  to  illustrate  the  point  under  discussion.  These 
data  are  stated  in  a  tabular  form : 

TABLE  LXXX 


Number  of  animals        

First 
experiment 
5 

Second 
experiment 

Days  fed      ,  _. 

182 

129 

Weight  per  animal,  average  for  period  '. 
Hay  eaten  per  day         ... 

Pounds 
.     1,412 
7.8 

Pounds 
1,237 
6.7 

Grain  eaten  per  day       .                                               .-  .  -  . 

23.9 

23. 

Daily  gain  per  animal 

2.39 

2.4 

Digestible  organic  matter  daily  per  animal        

19.5 

19. 

Digestible  organic  matter  per  1,000  pounds  live  weight  . 

13.8 

15.3 

In  1895-1896  the  Iowa  Agricultural  College  fed  steer 
calves  for  fourteen  months,  during  ten  of  which  a  record 
was  kept  of  all  the  food  consumed.  During  the  second 
period  the  steers  were  fattened  for  market.  This  particu- 
lar experiment  is  cited  because  the  animals  were  young 
and  all  the  conditions  were  favorable  to  the  maximum 
consumption  of  food  in  proportion  to  live  weight: 

TABLE  LXXXI 

First  Second 

period  period 

Number  of  animals      5  5 

Days  fed 120  181 

\ge  of  steers  at  beginning       9  to  10  mos.  16  to  17  mos. 

Pounds  Pounds 

Weight  per  animal,  average  for  period 766  1,197 

Coarse  food  eaten  daily  (partly  roots  and  green  fodder)          11  12.8 

Grain  eaten  daily  (partly  snapped  corn)      9  19.5 

Daily  gain  per  animal      2.04  2.11 

Gain  per  1,000  pounds  live  weight 2.66  1.76 

Digestible  organic  matter  daily  per  animal      ....           10.  14.1 
Digestible  organic  matter  daily  per  1,000  pounds  live 

weight 13.  11.8 


FEEDING  OF  POULTRY  401 

Although  it  is  possible,  for  some  purposes,  to  com- 
pound effective  rations  from  grain  alone  when  the  defi- 
ciency of  ash  is  made  good,  it  is  better  in  practice  to  use 
some  animal  food.  A  variety  of  grain  food  supplying 
enough  nitrogenous  matter  is  not  always  to  be  found,  and 
animal  foods  when  rich  in  protein,  as  most  of  them  are, 
prove  of  great  service;  for  with  them  can  be  freely  fed 
some  of  the  cheaper,  starchy  foods,  typical  among  which 
is  the  palatable  and  remarkably  efficient  Indian  corn.  For 
fattening  mature  fowls,  animal  food  is  not  so  important 
except  when  its  use  improves  the  palatability  of  the 
ration.  This  last  is  a  matter  always  to  be  considered. 

Succulent  vegetable  foods  are  eagerly  eaten  by  do- 
mestic fowls.  Aside  from  the  beneficial  effect  on  the 
health  of  the  birds,  it  is  important  to  use  such  foods  as 
far  as  possible,  for  the  nutriment  they  supply  is  cheaply 
obtained.  With  most  rations  the  more  nitrogenous 
fodders,  such  as  clover,  alfalfa,  and  very  immature 
grasses,  are  best.  These  foods  also  contain  more  of  the 
needed  lime  than  do  grains.  It  must  be  remembered, 
however,  that  fowls  are  not  fitted  to  depend  largely  on 
such  bulky  materials  while  production  is  rapid.  The 
goose  is  better  adapted  than  most  birds  to  live  by  grazing, 
but  the  liberal  use  of  the  more  concentrated  grain  and 
animal  foods  has  been  found  necessary  except  during 
the  idle  season. 

At  the  time  of  greatest  egg  production  the  choice  of 
bulky  foods  should  preferably  be  confined  to  those  of  the 
most  tender  and  succulent  nature.  Certain  experiments 
also  indicate  that  a  ration  which  contains  any  considera- 
ble proportion  of  dry  or  woody  coarse  fodder,  although 
finely  ground,  is  not  suited  to  young  chicks,  and  that 
only  the  more  succulent  kinds  of  bulky  foods,  like  the 
z 


402  THE  FEEDING  OF  ANIMALS 

first  shoots  of  grasses  and  clovers,  should  be  fed  in  the 
fresh  condition.  After  the  birds  approach  maturity  and 
growth  is  slower,  so  that  a  much  larger  proportion  of  the 
food  is  used  for  maintenance,  and  during  colder  weather 
when  the  heat  from  the  extra  energy  required  for  diges- 
tion is  useful,  more  of  the  coarse  foods  can  be  fed  with- 
out apparent  disadvantage. 

492.  Incidental  effects  of  the  food  with  laying  hens. — 
Another  reason,  sometimes  a  very  important  one,  for 
using  such  foods  as  young  clover,  fresh  or  dried,  is  the 
effect  on  the  color  of  the  egg  yolk.  Eggs  from  hens  which 
are  fed  only  certain  grain  and  animal  substances  gener- 
ally have  yolks  of  a  pale  yellow  color.  This  is  often 
objected  to  by  those  who  have  a  preference  for  eggs  with 
darker  orange-colored  yolks.  The  liberal  feeding  of  fresh 
or  dried  young  clover,  alfalfa,  or  grass  will  generally 
insure  the  deeper  coloration.  The  cause  for  this  frequent 
lack  of  what  may  be  considered  the  normal  yellow  color 
of  the  egg  yolk  is  not  well  known,  but  the  occurrence  of 
the  pale  color  can  be  generally  prevented  by  attention 
to  the  food. 

At  the  New  York  Experiment  Station,  pens  of  hens 
which  were  fed  alike  except  that  no  hay  or  green  food 
was  given  to  one,  while  three  others  had  different  amounts 
apportioned  by  geometrical  ratio,  of  clover  hay  alter- 
nated with  green  alfalfa,  produced  eggs  showing  marked 
differences  in  color.  The  orange-yellow  shade  of  the 
yolk  corresponded  directly  in  intensity  with  the  propor- 
tion of  hay  or  green  fodder  in  the  ration.  The  greenish 
color  of  the  white  also  varied  but  not  so  regularly.  Eggs 
from  each  lot  were  very  uniform  in  appearance. 

The  differences  in  flavor  and  other  qualities  which 
are  probably  caused  by  the  food  cannot  be  satisfactorily 


FEEDING  OF  POULTRY  403 

explained  at  present.  They  are,  however,  slight  with 
normal  rations.  In  general  the  color  of  the  shell  is  deter- 
mined by  the  breeding  or  by  the  individual  characteristics 
of  the  fowl. 

493.  Digestive  apparatus  of  birds  (Fig.  17). — The  pro- 
cess of  digestion  with  birds  is  essentially  similar  to  that  with 
mammals  although  there  are  important  differences  in  the 
apparatus  by  which  it  is  accomplished.  It  is  necessary 
to  know  something  of  the  general  arrangement  and 
working  of  the  digestive  canal  when  attempting  to  estab- 
lish proper  methods  of  feeding,  and  for  a  better  selec- 
tion and  combination  of  suitable  foods. 

Although  some  extinct  species  of  birds  were  well 
supplied  with  teeth,  existing  forms  have  the  mouth 
armed  only  with  a  horny  beak.  The  common  fowls 
must  swallow  grains  whole  but  are  able  to  tear  some 
food  into  small  fragments,  which  they  particularly  do 
when  feeding  the  young.  Ducks,  and  geese  more  especi- 
ally, have  the  mouth  supplied  with  laminae  which  serve 
to  cut  soft  herbage. 

In  birds  the  salivary  glands  are  small  and  the  lim- 
ited amount  of  saliva  probably  has  little  effect  on  the 
food. 

The  esophagus  is  of  great  caliber  and  very  expan- 
sible. It  is  dilated  in  the  cervical  portion  in  ducks  and 
geese.  In  gallinaceous  birds,  instead  of  this  dilatation 
there  is  attached  to,  and  forming  practically  a  part  of, 
the  esophagus,  the  reservoir  called  the  crop.  The  food 
is  temporarily  retained  in  the  crop,  but  is  changed  very 
little  other  than  being  softened  by  the  water  swallowed 
with  it,  the  small  amount  of  mucus,  and  the  inconse- 
quential amount  of  saliva.  The  high  temperature  doubt- 
less assists  this  softening  effect,  and  fermentation  also 


404  THE  FEEDING  OF  ANIMALS 

progresses  rapidly  when  food  is  retained  long  in  the  crop 
from  injury  or  by  overloading  with  coarse  material. 

The  divided  crop  of  pigeons  secretes,  with  both  sexes 
for  several  days  after  the  young  are  hatched,  a  thick 
milky  fluid  which  serves  to  feed  the  young  birds.  With 
other  domestic  birds  the  crop  serves  for  little  more  than 
a  temporary  retaining  reservoir. 

The  stomach,  which  is  a  single  organ  in  some  birds, 
is  represented  by  two  reservoirs  in  domestic  fowls.  The 
first,  through  which  the  food  passes  after  leaving  the 
crop,  is  the  glandular  stomach,  the  succentric  ventricle 
or  proventriculus,  and  the  second,  closely  connected,  is 
the  gizzard  or  muscular  stomach.  The  first,  from  its 
structure,  has  been  considered  the  true  stomach,  but  it  is 
now  believed  that  gastric  juice  is  secreted  in  the  gizzard. 
The  food  does  not  accumulate  in  the  first  stomach  but 
in  passing  through  carries  along  such  juices  as  are 
there  secreted. 

The  gizzard  is  a  powerful  grinding  apparatus.  There 
is  a  strong  lining  which  is  capable  of  resisting  great 
pressure  and  the  action  of  the  sharp  sand  and  pebbles. 
In  this  organ  the  grains  and  seeds,  with  other  materials, 
are  more  finely  ground  than  by  the  mastication  of  many 
other  animals. 

The  intestines  are  long  in  domestic  fowls.  While 
serving  the  same  purpose  as  in  mammals  and  having 
a  general  resemblance  to  the  mammalian  form,  they  do 
not  clearly  show  the  same  divisions.  The  diameter  is 
about  the  same  throughout.  The  caeca,  each  of  which  is 
closed  at  one  end  and  opens  into  the  intestines  at  the 
other,  seem  to  be  important  and  essential  modifications 
of  that  canal.  Each  caecum  is  from  6  to  7  inches  long 
in  mature  fowls.  Not  far  from  the  openings  of  the  caeca 


FEEDING  OF  POULTRY 


405 


the  intestine  ends  in  a  dilatation,  the  cloaca,  into  which 
the  genito-urinary  passages  also  open.  It  is  because  of 
the  mixing  here  of  the  undigested  residues  of  the  food 
with  the  secretions  from  the  kidneys  and  with  some  other 


9       OftigN    or    TLO/TIMQ    TOUTION   or    WMLL    IHTtSl 


FIG.  17.   Digestive  apparatus  of  the  common  fowl. 


406  THE  FEEDING   OF   ANIMALS 

products  of  metabolism,  that  an  accurate  estimation  of 
the  digestibility  of  food  by  birds  is  so  difficult.  No  satis- 
factorily accurate  methods  for  separating  some  of  the 
nitrogenous  residues  from  different  organs  seem  yet  to 
be  perfected. 

Into  the  intestine  shortly  after  it  leaves  the  gizzard 
two  ducts  from  the  liver  and  two  from  the  pancreas  enter, 
discharging  the  bile  and  pancreatic  j-uices.  The  liver,  as 
usual,  is  a  large  organ.  The  pancreas  also  is  very  largely 
developed,  and  extends  for  several  inches  along  the  duo- 
denal loop  of  the  intestines,  reaching  in  the  common 
fowl  a  length  of  over  5  inches. 

Altogether  the  structure  of  the  digestive  apparatus  of 
birds  indicates  extreme  efficiency  and  the  capacity  for 
rapid  work.  A  study  of  it  suggests,  also,  as  does  that  of 
any  complicated  and  delicately  adjusted  apparatus,  that 
it  should  not  be  overloaded  nor  violently  disturbed  when 
running  at  high  pressure.  It  may  be  said  to  run  at  high 
pressure  while  the  extremely  rapid  growth  of  young 
birds  occurs  and  during  the  extended  laying  season,  for 
the  resulting  products  call  for  an  uninterrupted  supply 
of  food  and  the  transformation  of  all  material  that  is 
available.  Chickens  of  two  pounds  weight  at  ten  weeks 
of  age  show  a  gain  over  the  weight  of  the  first  week  of 
nearly  1,700  per  cent.  Ducklings  five  pounds  in  weight 
at  nine  weeks  show  a  gain  during  about  eight  weeks  of 
3,900  per  cent.  Such  rates  of  growth  are  not  very  unusual 
for  young  fowls  under  favorable  conditions. 

494.  Constituents  of  the  body  of  the  hen.— Whether 
the  production  of  meat  or  of  eggs  is  the  prime  object, 
the  young  fowl  must  first  be  grown.  It  is  desirable,  then, 
to  consider  what  constituents  make  up  the  body  of  the 
animal,  for  all  must  be  derived  from  the  food.  Many 


FEEDING  OF  POULTRY  407 

slight  variations  in  composition  exist,  of  course,  but  there 
is  always  a  certain  approximation  to  the  normal  full- 
grown  animal. 

In  the  whole  body  of  the  common  fowl,  unless  especi- 
ally fattened,  not  far  from  one-half  of  the  dry  matter  is 
protein  and  about  8  per  cent  ash.  This  of  itself  would 
suggest  that  a  slow  growth  must  follow  the  use  of  foods 
containing  small  amounts  of  nitrogenous  and  mineral 
matter. 

Analyses  made,  mostly  by  Jenter  at  the  New  York 
Experiment  Station,  give  as  the  average  composition 
of  the  body  of  a  Leghorn  hen,  typical  of  the  laying  breeds, 
55.8  per  cent  of  water,  21.6  per  cent  of  protein,  3.8  per 
cent  of  ash,  and  17  per  cent  of  fat.  This  is  not  the  com- 
position of  the  edible  portion  alone  nor  of  the  carcass  as 
found  in  the  market,  but  that  of  the  whole  body,  bones, 
blood,  feathers,  and  all  the  viscera.  The  different  parts 
of  the  body  were  all  separately  analyzed.  Separate  analy- 
ses of  four  individual  hens  each  gave  a  close  approxima- 
tion to  the  average.  The  composition  of  the  body  of  a 
Leghorn  pullet  in  full  laying  was  little  different  from  the 
average  for  the  hens,  being  55.4  per  cent  of  water,  21.2 
per  cent  of  protein,  3.4  per  cent  of  ash,  and  18  per  cent 
of  fat. 

The  body  of  a  mature  capon  (Plymouth  Rock)  con- 
tained 41.6  per  cent  of  water,  19.4  per  cent  of  protein, 
3.7  per  cent  of  ash,  and  33.9  per  cent  of  fat.  If  the  extra 
amount  of  fat  were  removed,  the  composition  would  be 
very  similar  to  that  of  the  other  fowls.  In  younger  and 
immature  birds  the  percentage  of  fat  is  very  much  less 
than  in  older  birds. 

495.  Composition  of  eggs. — The  egg,  which  aside 
from  the  shell  is  potentially  a  chick,  shows  in  the  general 


408  THE  FEEDING  OF  ANIMALS 

proportions  of  the  constituents  a  striking  resemblance  to 
the  body  of  the  grown  bird.  Of  the  dry  matter  of  eggs 
analyzed,  aside  from  the  shell,  49.8  per  cent  on  the  aver- 
age was  protein,  3.5  per  cent  ash,  and  38.6  per  cent 
fat.  Of  the  dry  matter  of  the  bodies  of  hens  48.9  per 
cent  was  protein,  8.6  per  cent  ash,  and  38.5  per  cent  fat. 
Of  the  total  dry  matter  in  the  entire  egg,  35.6  per 
cent  is  ash,  25.9  per  cent  fat,  and  about  33.3  per  cent  pro- 
tern,  or  38.5  per  cent  if  estimated  by  difference.  The 
fresh  egg  with  a  good  firm  shell  consists  of  about  11.4  per 
cent  shell,  65.7  per  cent  of  water,  8.9  per  cent  of  fat,  11.4 
per  cent  of  protein  by  factor,  or  13.2  per  cent  by  differ- 
ence, and  .8  per  cent  of  ash  constituents  aside  from  the 
shell.  Of  this  ash  53.7  per  cent  is  phosphoric  acid.  Over 
.2  per  cent  of  the  edible  portion  of  the  egg  is  phosphorus. 
This  composition  is  the  average  from  twenty-four  analy- 
ses by  Thompson,  and  eighteen  by  Wheeler,  represent- 
ing over  400  eggs  from  hens  of  several  breeds  under  dif- 
ferent rations.  None  of  the  analyses  differed  much  from 
the  average. 

496.  Necessity  for   considering   the   water-supply. — 
In  the  products,  which  have  been  mentioned,  as  in  most 
animal  products  sought  by  feeding,  there  is  always  a 
large  amount  of  water.    In  every  dozen  eggs  there  is  a 
pint  of  water.    Aside  from  that  necessary  for  construc- 
tive use  there  is  required  for  the  activities  of  the  living 
animal  a  free  supply.    Particular  mention  is  made  of  the 
necessity  for  water,  because  its  great  importance  is  some- 
times overlooked,  for  an  especially  provided  supply  is 
not  necessary  under  some  circumstances.   Instances  occur 
when  the  lack  of  water  is  the  cause  of  ill  success. 

497.  Efficiency  of   protein   from   animal   sources  for 
fowl. — Mention  of  the  characteristics  and  composition 


FEEDING  OF  POULTRY  409 

of  the  different  nutrients  of  the  food  and  a  discussion  of 
their  functions  will  be  found  elsewhere  in  this  volume. 
The  facts  apply  to  the  feeding  of  poultry  as  well  as  to 
that  of  other  animals. 

It  appears  from  present  knowledge  that  protein 
derived  from  animal  sources  is  more  efficient  for  certain 
uses,  particularly  the  feeding  of  ducklings,  than  that 
derived  from  vegetable  foods.  Previous  mention  has  been 
made  of  experiments  at  the  New  York  Experiment  Sta- 
tion, the  results  of  which  accord  with  this  assumption. 
The  rations  which  contained  animal  food  proved  much 
more  efficient  than  those  of  vegetable  origin,  the  latter 
having,  according  to  the  ordinary  methods  of  estimation, 
the  same  nutritive  value  as  the  former. 

498.  Ash  constituents  important  for  egg  production. — 
It  seems  probable  that  the  ash  constituents  have  some- 
times not  been  sufficiently  considered  in  feeding.  While 
the  importance  of  the  mineral  nutrients  can  be  largely 
overlooked  without  serious  practical  disadvantage  when 
feeding  some  animals  for  certain  purposes,  it  must  be 
given  consideration  when  feeding  domestic  fowls.  While 
in  milk,  for  instance,  about  5  per  cent  of  the  dry  matter 
is  ash,  in  eggs  over  35  per  cent  of  the  dry  matter  is  repre- 
sented by  the  mineral  constituents. 

The  shell  of  the  egg,  which  represents  about  11  per 
cent  of  the  fresh  egg,  consists  almost  entirely  of  carbonate 
of  lime.  Most  grain  foods,  which  naturally  constitute  the 
bulk  of  ordinary  rations,  contain  little  mineral  matter 
and  the  amount  of  lime  is  notably  low.  For  simply  sup- 
plying the  deficiency  of  material  for  the  egg  shell,  car- 
bonate of  lime  in  the  form  of  oyster  shell  can  be  used. 
This  was  shown  in  experiments  at  the  New  York  Experi- 
ment Station  made  with  laying  hens  after  they  were 


410  THE  FEEDING  OF  ANIMALS 

closely  confined  on  a  clean  floor  for  over  three  weeks.  It 
was  then  found  that  about  nine-tenths  of  the  lime  in  the 
egg  shell  was  unaccounted  for  in  the  food  aside  from  the 
oyster  shells  which  were  fed. 

While  less  than  10  per  cent  of  the  body  of  a  fowl  is 
mineral  matter,  it  consists  largely  of  phosphate  of  lime 
and  exceeds  in  proportion  that  of  many  foods.  The  bony 
framework  is  also  rapidly  formed  in  the  growing  bird  so 
that  mineral  matter  is  in  imperative  demand.  The 
results  of  many  trials  made  at  the  New  York  Experi- 
ment Station  are  clearly  in  accord  with  this  assumed 
need.  As  has  been  previously  mentioned,  the  addition 
of  phosphate  of  lime  from  several  sources  to  rations  for 
young  fowls  has  noticeably  increased  their  efficiency. 

499.  Common  salt  a  necessity  for  fowls. — Common 
salt  in  considerable  quantity  is  a  necessity  to  the  living 
animal.   Some  foods  contain  a  probably  sufficient  amount 
but  in  others  the  proportion  is  very  small.    In  order  to 
make  sure  of  an  excess,  and  to  avoid  any  possible  defi- 
ciency, it  is  well  to  add  salt  regularly  to  the  food,  espec- 
ially when  it  also  increases  the  palatability  of  the  ration. 
About  five  ounces  in  every  100  pounds  of  food  has  been 
found  a  safe  proportion.    Fowls  regularly  accustomed  to 
salt  are  not  likely  to  eat  an  injurious  quantity  of  very 
salty  material  when  it  is  accidentally  within  their  reach. 
Pigeons  are  very  fond  of  salt  and  a  liberal  allowance  is 
generally  considered  necessary  to   insure  health  in  the 
loft. 

500.  Supply  of  grit  for  fowls. — Fowls  at  liberty  are 
generally  able  to  find  grit  enough  in  the  form  of  sharp 
pebbles  and  sand  to  facilitate  the  grinding  which  occurs 
in  the  gizzard.    When  they  are  confined  or  do  not  have 
extended  range,  sharp  and  hard  grit  of  some  kind  should 


FEEDING  OF  POULTRY  411 

always  be  freely  supplied.  Clean,  sharp  sand  is  useful 
for  the  very  young  birds  and  is  quite  generally  considered 
an  essential  part  of  all  mixtures  fed  to  ducklings.  Good 
results  accompany  its  free  use. 

501.  Feeding  standards  for  fowls. — In  studying  and 
comparing  different  rations,  it  is  not  possible  to  consider 
all  the  combinations  that  can  be  made  of  the  many  foods. 
It  is  only  practicable  to  consider  foods  with  reference  to 
their  varying  proportions  of  constituents.  The  only 
portion  of  these  constituents  of  nutritive  value  is  that 
which  can  be  digested.  Therefore,  in  compounding 
rations,  we  are  guided  primarily  by  the  amount  of  the 
digestible  nutrients  supplied  by  the  food;  and  feeding 
standards  are  for  convenience  limited  to  a  statement  of 
the  assumed  requirements  in  terms  of  digestible  pro- 
tein, ash,  carbohydrates,  and  fat.  The  bulk  of  the  ration 
supplying  these  nutrients  must  also,  of  course,  fall  within 
certain  limits.  In  the  absence  of  enough  specific  data, 
calculations  must  be  based  on  the  coefficients  of  digesti- 
bility observed  for  other  animals.  These  afford  safe 
enough  approximations  for  present  use,  for  the  feeding 
standards  must  be  largely  provisional. 

Growth  and  egg  production  can  only  be  sustained  by 
the  food  in  excess  of  that  required  to  support  life,  although 
egg  production  can  temporarily  occur  at  the  partial 
expense  of  the  body.  The  amount  of  food,  then,  required 
for  simple  maintenance  puts  a  limit  on  one  side  to  an 
efficient  and  profitable  ration.  In  the  other  direction,  it 
is  only  limited  by  the  capabilities  of  the  individual  ani- 
mal. So  the  highest  possibilities  depend  altogether  on 
the  intelligent  judgment,  and  careful,  daily  attention  of 
the  experienced  feeder.  In  a  general  way  only  averages 
can  be  considered. 


412 


THE  FEEDING  OF  ANIMALS 


502.  Maintenance  rations  for  fowls. — A  number  of 
feedings  trials  made  at  the  New  York  Experiment  Sta- 
tion supply  information  relative  to  the  amount  of  food 
required  for  simple  maintenance.  The  amount  varies, 
as  might  be  expected,  with  the  size  of  the  animal.  The 
larger  fowls  required  more  food  but  much  less  for  each 
pound  of  live  weight.  These  feeding  trials  did  not  cover 
any  molting-period  and  egg  production  was,  for  the  time, 
suspended.  From  the  data  secured  maintenance  rations 
have  been  deduced  which  correspond  very  closely  to 
those  actually  fed  for  quite  extended  periods  during 
which  practically  no  change  in  live  weight  occurred.  The 
data  were  from  an  aggregate  of  52  capons,  averaging  by 
different  lots  from  9  to  12  pounds  in  weight,  for  158  days' 
feeding,  and  from  60  hens  ranging  from  3  to  7  pounds  in 
weight  for  150  days'  feeding. 

The  rations  are  stated  in  the  following  tabulated  form: 

TABLE  LXXXV.     MAINTENANCE   RATIONS.    DIGESTIBLE  NUTRI- 
ENTS A  DAY  FOR  EACH  100  POUNDS  LIVE  WEIGHT 


Total  dry 
matter 

Ash 

Protein 

Carbohy- 
drates 

Fat 

Fuel 
value 

Nutritive 
ratio 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Cal. 

Capons  of  9  to  12  Ibs.wt 

2.3 

.06 

.3 

1.74 

.2 

4,600 

1:7.5 

Hens  of  5  to  7  Ibs.  wt. 

2.7 

.1 

.4 

2. 

.2 

5,300 

1:6.2 

Hens  of  3  to  5  Ibs.  wt. 

3.9 

.15 

.5 

2.95 

.3 

7,680 

1:7.4 

503.  Rations  for  laying  hens. — Hens  in  full  laying 
seem  to  require  rations  which  have  a  larger  relative  con- 
tent of  protein  and  ash,  and  which  show  an  increase  in 
fuel  value  of  from  15  to  40  per  cent,  according  to  size, 
over  those  required  for  maintenance.  The  following 
standards  approximate  the  requirements  for  two  general 
groups  not  sharply  separated. 


FEEDING  OF  POULTRY 


413 


TABLE  LXXXVI.  RATIONS  FOR  HENS  IN  FULL  LAYING.  DI- 
GESTIBLE NUTRIENTS  A  DAY  FOR  EACH  100  POUNDS  LIVE 
WEIGHT. 


Total  dry 
matter 

Ash 

Protein 

Carbohy- 
drates 

Fat 

Fuel 
value 

Nutritive 
ratio 

Hens  of  5  to  8  Ibs.  wt. 
Hens  of  3  to  5  Ibs.  wt. 

Lbs. 
3.3 
5.5 

Lbs. 
.2 
.3 

Lbs. 
.65 
1. 

Lbs. 
2.25 
3.75 

Lbs. 
.2 
.35 

Cal. 
6,240 
10,300 

1:4.2 
1:4.6 

These  standards  are  not  absolute  and  inflexible  rules, 
for  such  would  not  be  justified  by  a  thousand  times  the 
number  of  available  data.  They  supply  a  definite  start- 
ing point  and  are  not  supposed  to  obviate  the  use  of  judg- 
ment. Because  it  is  found  convenient,  on  account  of 
different  requirements  and  capabilities,  to  divide  hens 
into  two  groups,  it  should  not  be  presumed  that  a  hen  just 
under  five  pounds  in  weight  must  always  have  one  ration  or 
a  hen  just  over  five  pounds  must  always  have  the  other. 

A  ration  which  corresponds  to  the  standard  given  for 
maintenance  for  hens  of  the  larger  size  could  be  com- 
posed of  one  pound  of  cracked  corn,  one  pound  of  corn 
meal,  one-half  pound  each  of  ground  oats,  wheat  mid- 
dlings, and  clover  hay,  one-fourth  pound  of  fresh  bone 
and  two  ounces  of  meat  scraps. 

The  following  stated  ration  is  given  as  an  illustration 
of  one  which  would  supply  the  nutrients  called  for  in  the 
standard  for  laying  hens  of  the  larger  size:  One  pound 
of  cracked  corn,  three-fourths  pound  of  wheat,  three- 
fourths  pound  of  corn  meal,  one-half  pound  each  of  wheat 
middlings,  buckwheat  middlings,  and  animal  meal,  two- 
thirds  pound  of  fresh  bone,  and  three-fourths  pound  of 
young  green  alfalfa. 

504.  Rations  for  young  birds. — The  requirements  of 
the  rapidly-growing  young  fowl  are  so  constantly  chang- 


414 


THE  FEEDING  OF  ANIMALS 


ing  that  a  satisfactory  average  ration  for  any  extended 
period  cannot  be  easily  formulated.  In  the  following 
statement  of  rations  for  chicks,  they  are  averaged  for 
periods  of  two  weeks  at  different  ages  during  the  time  of 
most  rapid  growth.  The  ration  for  the  last  period  will 
suffice  for  several  weeks  longer,  although  the  amount 
required  to  the  100  pounds  live  weight  will  gradually 
diminish  up  to  maturity.  For  fattening  nearly  mature 
fowls,  a  ration  with  a  wider  nutritive  ratio  of  about  1 : 8 
can  be  liberally  fed  for  limited  periods. 

The  duck  grows  faster  than  the  common  fowl  and 
more  food  is  required  during  an  equal  time.  Rations  for 
ducklings  differing  somewhat  from  those  for  chicks  are 
given  separately. 

TABLE  LXXXVII.    RATIONS  FOR  CHICKS.    DIGESTIBLE  NUTRIENTS 
A  DAY  FOR  EACH  100  POUNDS  LIVE  WEIGHT 


Total 
dry 
matter 

Ash 

Protein 

Carbohy- 
drates 

Fat 

Fuel 
value 

Nutri- 
tive 
ratio 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Cal. 

For  the  first  2  weeks     . 

10.1 

.5 

2. 

7.2 

.4 

18,800 

1:4.1 

From  2  to  4  weeks  of  age 

9.6 

.7 

2.2 

6.2 

.5 

17,730 

1:3.4 

From  4  to  6  weeks  of  age 

8.6 

.6 

2. 

5.6 

.4 

15,640 

1:3.3 

From  6  to  8  weeks  of  age 

7.4 

.5 

1.6 

4.9 

.4 

13.780 

1:3.7 

From  8  to  10  weeks  of  age 

6.4 

.5 

1.2 

4.4 

.3 

11,680 

1:4.3 

From  10  to  12  weeks  of  age 

5.4 

.4 

1. 

3.7 

.3 

10,000 

1:4.4 

RATIONS  FOR  DUCKLINGS.     DIGESTIBLE   NUTRIENTS  A   DAY  FOR 
EACH  100  POUNDS  LIVE  WEIGHT 


Total 
dry 
matter 

Ash 

Protein 

Carbohy- 
drates 

Fat 

Fuel 
value 

Nutri- 
tive 
ratio 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

CaL 

For  the  first  2  weeks 

17.2 

1.6 

4. 

11.2 

1.4 

34,180 

1:3.7 

From  2  to  4  weeks  of  age 

17. 

1.5 

4.1 

10.1 

1.3 

31,900 

1:3.2 

From  4  to  6  weeks  of  age 

11.2 

.8 

2.7 

7. 

.7 

21,000 

1:3.3 

From  6  to  8  weeks  of  age 

8. 

.6 

1.7 

5.2 

.5 

14,940 

1:3.8 

From  8  to  10  weeks  of  age 

7. 

.5 

1.4 

4.7 

.4 

13,030 

1:4.1 

From  10  to  15  weeks  of  age 

4.6 

.3 

.9 

3.2 

.2 

8,470 

1:4.1 

FEEDING  OF  POULTRY  415 

As  an  example  of  a  day's  ration  which  would  cor- 
respond to  the  requirements  of  the  standard  given  for 
young  chicks  during  the  second  week  the  following  is 
stated:  Four  pounds  of  cracked  wheat,  two  pounds  of 
granulated  oatmeal,  three  pounds  of  corn  meal,  one-half 
pound  each  of  wheat  middlings,  buckwheat  middlings, 
ground  oats,  and  old  process  linseed  meal,  two  and  one- 
fourth  pounds  of  animal  meal,  and  two  and  three-fourths 
pounds  of  young  green  alfalfa.  This  would  feed  from 
800  to  1,000  chicks  of  this  age. 

Another  ration  in  accord  with  the  standard  given 
for  ducklings  about  three  weeks  old  might  be  consti- 
tuted as  follows:  Eight  pounds  corn  meal,  three  pounds 
wheat  middlings,  two  pounds  ground  barley,  two  pounds 
of  old  process  linseed  meal,  six  pounds  of  animal  meal, 
two  pounds  of  fresh  bone,  and  three  pounds  of  young 
green  alfalfa.  This  and  other  specimen  rations  are  given 
under  the  assumption  that  free  supplies  of  sharp  grit,  as 
well  as  water,  are  also  provided. 

505.  Adaptability  of  various  foods  for  fowls. — A  con- 
sideration of  the  adaptability  of  the  different  foods, 
aside  from  their  composition,  and  of  the  apparent  require- 
ments of  the  young  at  different  periods  suggests  a  ration 
somewhat  wider  in  nutritive  ratio  for  the  first  few  days 
than  for  some  weeks  afterward. 

In  providing  a  ration,  it  may  be  possible  to  devise 
one  in  accord  with  the  formal  standard  which  will  be 
decidedly  inefficient  at  times  if  the  chemical  composi- 
tion and  coefficients  of  digestibility  are  alone  considered. 
The  adaptability  of  foods  that  are  palatable  must  be  con- 
sidered. The  difference  in  the  energy  required  to  digest 
various  foods  which  can  supply  equal  proportions  of 
digestible  matter  may  be  important  sometimes. 


416  THE  FEEDING  OF  ANIMALS 

A  large  number  of  the  ordinary  grains  seem  prac- 
tically interchangeable  and  many  grain  by-products  can 
be  freely  substituted  for  different  whole  grains  or  for 
each  other  and  all  combined  as  desired.  But  some  foods, 
such  as  cottonseed  meal,  do  not  seem  suited  to  common 
fowls,  even  in  very  small  quantities.  Linseed  meal  can 
be  fed  more  freely,  but  the  unground  flaxseed  is  less 
satisfactory.  It  is  probable  that  oats,  whole  or  ground, 
which  appear  so  valuable  sometimes,  should  not  be  freely 
used  at  other  times.  About  30  per  cent  of  the  entire 
grain  is  hull.  To  obtain  the  available  material  from  this 
requires  an  expenditure  of  energy  that  can  be  better 
applied  during  periods  of  rapid  transformation,  espe- 
cially during  the  first  few  weeks  of  the  young  bird's  growth. 
The  products  of  the  oat  kernel,  however,  from  which 
the  hull  has  been  separated  are  in  the  unquestioned  class 
of  foods.  The  same  observation  applies  to  buckwheat, 
some  kinds  of  pea  meal,  and  to  certain  other  foods  less 
commonly  used,  containing  a  large  proportion  of  crude 
fiber.  Reference  to  this  point  has  been  made  before  under 
the  topic  of  coarse  and  bulky  foods. 

Primary  consideration  has  naturally  been'  given  to 
those  domestic  fowls  upon  which  we  depend  for  the 
great  bulk  of  eggs  and  meat.  Other  kinds  are  of  consider- 
able importance  in  certain  localities,  or  often  to  the 
fancier,  but  concerning  them  not  enough  is  recorded  to 
establish  separate  feeding  standards.  It  is  probable  that 
their  requirements  will  be  found  to  correspond  fairly 
well  with  those  of  either  the  duck  or  of  the  common  fowl. 
The  general  food  of  the  turkey  is  similar  to  that  of  the 
common  fowl  but  it  should  be  less  artificial,  and  con- 
ditions of  general  feeding,  more  nearly  resembling  those 
which  exist  in  a  wild  state,  are  required. 


FEEDING  OF  POULTRY  417 

506.  Knowledge  of  the  nutrition  of  fowls  limited. — 
Unsatisfactory  as  is  our  present  knowledge  of  the  funda- 
mental laws  which  underlie  the  science  of  nutrition 
applied  to  man  and  other  animals,  there  are  nevertheless 
volumes  of  carefully  collected  data  that  make  it  possible 
to  ascribe  fairly  narrow  limits  to  their  operations.  Com- 
pared with  mammals,  however,  the  class  of  birds  has 
received  very  little  consideration.  There  have  been  a 
few  careful  studies  made,  but  for  lack  of  enough  informa- 
tion our  feeding  must  be  guided  by  the  rules  applying  in 
common  to  all  animals.  Undoubtedly,  the  accepted  laws 
of  nutrition  observed  for  other  animals  are  applicable  in  a 
general  way  to  domestic  fowls,  and  it  is  safe  to  apply  in 
the  light  of  the  specific  data  we  have  any  general  prin- 
ciples of  feeding  that  have  already  been  established.  This 
has  been  done  in  formulating  the  feeding  standards  which 
are  here  presented,  and  all  available  data  of  a  reliable 
character  have  been  considered.  There  have  not  been 
enough,  however,  to  justify  narrow  limitations,  and  the 
suggested  standards  should  not  be  considered  final  and 
unchangeable.  They  simply  represent  the  averages  of 
rations  which,  under  careful  management  and  like  con- 
ditions, have  given  better  results  than  various  other 
rations  with  which  they  have  been  contrasted.  Slight 
modifications  were  made  in  accord  somewhat  with  the 
habits  of  the  different  fowls  and  with  a  consideration  of 
the  character  of  the  products  desired.  It  is  important 
that  the  feeder,  while  following  such  standards  in  a  gen- 
eral way,  should  give  enough  consideration  to  the  sub- 
ject to  make  modifications  suited  to  the  species  and  breed 
and  to  his  particular  conditions  of  market  and  farm. 


AA 


CHAPTER  XXIV 
THE  RELATION  OF  FOOD  TO  PRODUCTION 

ONE  of  the  questions  much  discussed  by  farmers, 
and  which  has  an  important  bearing  upon  the  economics 
of  animal  husbandry,  is  the  food  cost  of  the  various 
animal  products.  To  illustrate,  a  herd  of  cows  consumes 
a  certain  quantity  of  food  and  produces  a  certain  weight 
of  milk,  milk  solids,  cheese,  or  butter,  according  to  the 
terms  in  which  we  state  the  production.  If  the  same 
food  is  fed  to  a  lot  of  steers  a  certain  increase  in  their 
live  weight  is  secured.  There  is  in  each  case  a  relation 
of  quantity  between  the  food  and  the  product.  The  food 
cost,  that  is,  the  food  consumption,  involved  in  growing 
a  pound  of  beef,  is  quite  unlike  the  food  requirements  for 
producing  a  pound  of  pork,  a  pound  of  veal,  or  a  pound 
of  eggs.  If  we  consider  merely  food  expenditure,  that 
branch  of  animal  husbandry  is  most  economical  of  raw 
materials  in  which  the  largest  proportion  of  the  food  dry 
substance  is  converted  into  some  new,  useful  product,  or, 
differently  stated,  where  the  food  units  bear  the  lowest 
ratio  to  a  unit  of  product. 

507.  Food  unit  defined. — In  presenting  the  matter  it  is 
necessary  to  first  define  our  units.  Certainly  it  cannot  be  a 
pound  of  food  as  eaten.  One  farmer  feeds  his  cows  silage  or 
roots,  and  grain,  with  but  little  hay,  while  another  fattens 
steers  on  dry  food  alone.  A  comparison  of  production  in 
the  two  instances  on  the  basis  of  the  gross  weight  of  food 
consumed  would  be  absurd,  because  with  the  cows  the 

(418) 


RELATION  OF  FOOD   TO  PRODUCTION  419 

dry  matter  is  largely  diluted  with  water.  It  would  be 
equally  absurd  to  accept  the  dry  matter  in  the  ration  as 
a  standard.  In  instituting  a  comparison  between  bo  vines 
and  swine,  we  must  remember  that  the  former  consume 
materials  much  less  digestible  than  do  the  latter,  and  so  a 
unit  weight  of  food  does  not  represent  the  same  weight  of 
available  nutrients  with  the  two  classes  of  animals. 

We  should,  so  far  as  possible,  reduce  rations  to  their 
units  of  nutritive  value,  and  so  the  digestible  dry  matter 
is  now  the  nearest  approach  we  can  make  to  a  basis  for 
comparing  rations  with  each  other  or  with  the  produc- 
tion which  they  sustain.  It  follows,  then,  that  if  we  wish 
to  show  the  comparative  economy  of  production  in  dairy 
farming  and  in  beef  farming,  food  alone  considered,  we 
should  express  this  relation  on  one  side  in  terms  of  digesti- 
ble dry  food  substance.* 

508.  The  unit  of  production. — What  shall  we  con- 
sider as  a  unit  of  production?  We  may  answer  this 
question  from  two  standpoints.  We  may  measure  pro- 
duction by  the  quantity  of  the  commercial  article  which 
the  farmer  places  on  the  market,  or  by  the  actual  contribu- 
tion which  any  given  production  makes  to  the  food 
resources  of  the  human  family.  More  specifically  stated, 
we  may  determine  the  relation  of  a  unit  of  digestible 
food  substance  to  the  live  animal,  beef,  pork,  milk,  cheese, 
butter,  or  eggs  resulting  from  its  use,  and  calculate  the 
ratio  of  any  one  of  these  to  the  actual  nutrients  con- 
sumed, or  we  may  ascertain  the  ratio  of  food  consump- 
tion to  the  edible  dry  substance  in  the  various  animal 

*Since  the  above  was  written,  we  are  able  to  reduce  the  food  unit 
for  production  to  what  is  termed  production  value.  This  is  more  funda- 
mental than  the  digestible  matter  as  a  basis  for  comparison.  The  com- 
parisons hereafter  made  are,  however,  with  the  digestible  matter  con- 
sumed as  related  to  the  unit  of  production. 


4:20  THE  FEEDING  OF  ANIMALS 

products.  The  latter  is  the  important  ratio  to  consider 
if  we  are  seeking  to  learn  how  we  can  most  efficiently 
apply  farm  crops  to  the  sustenance  of  the  human  family. 

509.  Factors  involved  in  food  economics. — This  study 
of  food  economics  requires  a  knowledge  of  several  factors. 
In  the  first  place,  we  must  have  the  information  coming 
from  feeding  experiments,   where  a  careful  record  has 
been  kept  of  the  kind  and  amount  of  food  consumed  and 
the  weight  of  the  resulting  growth,  milk,  eggs,  or  what  not. 
This  information  must  be  supplemented  by  a  knowledge 
of  the  digestibility  of  feeding-stuffs,  of  the  ratio  between 
the  live  animal  or  other  gross  product  and  the  commer- 
cial products,  and  of  the  composition  and  proportion  of 
edible  material  supplied  by  the  commercial  article.    For 
instance,  we  find  it  takes,  on  the  average,  7.4  pounds 
of  digestible  organic  substance  in  the  ration  to  produce 
1  pound  of  growth  in  a  steer,  and  we  have  learned  by 
slaughter  tests  that  the  average  per  cent  of  carcass  for 
97  animals  was  61.4,  and  by  the  butchers'  and  chemists' 
analyses,  that  the  carcass  contains  an  average  of  33.2 
per  cent  of  edible  dry  matter.   From  these  data  it  is  easy 
to  calculate  that  12  pounds  of  digestible  food  are  needed 
for  the  growth  of  1  pound  of  carcass  or  36.3  pounds  for 
the  growth  of  1  pound  of  edible  beef  solids. 

510.  Relation    of   food    to    production   with   various 
species. — The  following  tables  give  the  data  upon  which  is 
based  the  productive  power  of  food  when  utilized  by 
the  various  classes  of  animals.    Data  of  this  kind  are 
practically  our  only  means  of  studying  the  economics 
of  producing  those  human  foods  which  are  most  costly 
in  proportion  to  their  nutritive  value,  a  study  which  is 
very  important  wherever  it  becomes  necessary  to  econo- 
mize energy.    It  shows  the  coefficients  of  efficiency  of 


RELATION  OF  FOOD    TO  PRODUCTION 


421 


various  species  of  animals  in  maintaining  human  life. 
The  sources  of  all  these  figures  are  not  given,  for  they 
are  so  numerous  as  to  make  this  difficult. 

It  is  true,  in  general,  that  prices  are  proportional  to 
the  cost  of  production.  If,  therefore,  natural  resources 
are  to  be  utilized  for  human  sustenance  in  the  most 
efficient  way  and  the  cost  of  living  brought  to  the  lowest 
possible  point,  the  raw  materials  of  the  farm  should  be 
applied  to  the  production  of  those  animal  foods  that  are 
most  cheaply  grown. 

The  time  will  probably  come  when  the  relation  of 
population  to  land  areas  will  be  such  as  to  make  necessary 
an  application  of  food  economics  along  this  line. 

TABLE  LXXXVIIL  PRODUCTION  BY  FARM  ANIMALS.  PROPORTIONS 
OF  CARCASS  AND  EDIBLE  SUBSTANCE 


Number 
of 
animals 

Carcass 
in  per  cent 
of  live 
weight    . 

Per  cent* 
of  edible 
dry  matter 
in  carcass 

Per  cent  of 
edible  dry 
matter  in 
live  animal 

Steers,  general  average     .    . 
Steers  Iowa              .    . 

97 
5 

61.4 
64. 

33.2 
33.2 

20.4 
21.2 

Steers,  Kansas  
Steers  Mainet 

5 

8 

61.4 

57.7 

33.2 
32.3 

20.4 
18.6 

Sheep      

4 

50.7 

37.4 

19. 

Lambs     

44 

50.7 

33.7 

17.1 

Lambs,  Iowa     
Swine,  general  average     . 
Pigs  Iowa         

133 
97 
56 

54. 
81.2 
77.9 

33.7 
62.7 
62.7 

18.2 
50.9 

48.8 

Calves     

23 

57.2 

22.2 

12.7 

Fowl,  large     .    .    . 
Fowl,  small    
Chickens,  broilers     .... 
Bess 

12 

7 
107 

34§ 

80.8 
78. 
82.1J 

88.811 

27. 
27. 
14.7 
26.3 

21.8 
21.1 
12.1 
23.3** 

*  From  Bull.  No.  28,  Office  of  Experiment  Stations.   Revised  edition. 
t  Grown  from  calfhood,  entire  bodies  analyzed. 
j  Not  drawn. 
§  Number  of  samples. 
!  Per  cent  after  removing  shells. 
**In  eggs  with  shells. 


422 


THE  FEEDING  OF  ANIMALS 


TABLE  LXXXIX.    RELATION  OF  FOOD  TO  PRODUCT 


Diges- 

Diges- 

Diges- 

Number 

_f 

Number 

tible  org. 
substance 

tible  org. 
substance 

tible  org. 
substance 

OI 

experi- 
ments 

of 
animals 

produ- 
cing 1  Ib. 

produ- 
cing 1  Ib. 

aroducing 
lib. 

increase 

increase 

increase 

live  wt. 

carcass 

edible  sol 

Pounds 

Pounds 

Pounds 

Milk,  average      

61 

391 

.72 

5.55 

Milk,  New  York*       .... 

113t 

30 

.63 

4.85 

Steers,  average    

32 

242 

7.4 

12. 

36.3 

Steers,  la.,  growth  9  to  24  m. 

1 

5 

5.97 

9.33 

28.1 

Steers,  Kansas,  3  years  old 

1 

8 

8.08 

13.16 

39.6 

Steers,  Maine      

1 

4 

6.65 

11.5 

35.7 

Sheep  and  lambs,  average     i 

11 

122 

7.2 

14.2 

37.9 

Lambs,    Iowa,   growth   while 

fattening      

2 

133 

5.63 

10.43 

30.9 

Swine,  §  average      

277 

1,385 

3.29 

4. 

6.4 

Pigs,  Iowa   

1 

56 

3.03 

3.89 

6.2 

Calves,  average      

3 

30 

1.57$ 

2.7 

12.3 

Fowl,  large,  to  5  or  6  mos.ll  . 

6 

5.1 

6.3 

23.4 

Fowl,  small,  to  5  or  6  mosJ 

6 

5.1 

6.5 

24.2 

Chickens,  broilers,  12  wks.1 

15 

3.48** 

4.2 

28.8 

Eggsll    

14 

139tt 

4.56§§ 

5.1 

19.6 

*Extending  over  seven  years. 

tShort  periods. 

§Deduced  from  compilation  by  Dr.  Armsby  for  U.  S.  Dept.  of  Agriculture. 

JDry  matter,  mostly  from  milk,  practically  all  digestible. 

II  Unpublished  data  from  experiments  at  the  New  York  Agric.  Exp.  Station. 
**4.35  Ibs.  dry  matter,  assumed  to  be  80  per  cent  digestible. 
ttEgg  product,  100  eggs  per  year. 
§§85.7  Ibs.  dry  matter,  assumed  to  be  80  per  cent  digestible. 

The  figures  of  the  foregoing  tables  can  be  regarded 
as  being  trustworthy  for  average  conditions.  They  are 
obtained  from  the  recorded  data  of  experiment  stations, 
and  involve  a  large  number  of  observations  with  dairy 
cows  and  with  growing  and  fattening  animals. 

In  most  cases  the  amount  of  digestible  matter  in  the 
ration  is  calculated  from  the  average  coefficients  of 
digestibility. 

The  facts  brought  out  by  this  study  of  the  relation 
of  food  to  product  are  emphatic  and  suggestive.  In 
order  to  display  them  as  clearly  as  possible  there  are 
shown  in  the  next  table  the  quantities  of  the  various 


RELATION  OF  FOOD   TO  PRODUCTION 


423 


commercial  animal  products,  and  of  human  food  in 
animal  forms,  which  can  be  produced  by  the  use  of  a 
quantity  of  cattle  food  containing  100  pounds  of  digesti- 
ble organic  matter: 


TABLE  XC.    RELATION  OF  FOOD  TO  PRODUCT 


Produced  by  100  Ibs. 

digestible    organic 

matter  in  ration 


Marketable 
product 


Edible 
solids 


Milk,  general  average       

Milk,  New  York  experiments 

Cheese,  green 

Butter 

Steers,  general  average,  live  weight 

Steers,  Iowa,  live  weight 

Steers,  Kansas,  live  weight 

Steers,  Maine,  live  weight 

Steers,  general  average,  carcass      

Steers,  Iowa,  carcass 

Steers,  Kansas,  carcass 

Steers,  Maine,  carcass      

Sheep  and  lambs,  general  average,  live  weight 

Lambs,  Iowa,  live  weight 

Sheep  and  lambs,  general  average,  carcass 

Lambs,  Iowa,  carcass       

Swine,  general  average,  live  weight 

Swine,  Iowa,  live  weight      

Swine,  general  average,  carcass 

Pigs,  Iowa,  carcass 

Calves,  live  weight 

Calves,  carcass . 

Fowl,  large,  live  weight 

Fowl,  small,  live  weight       

Fowl,  dressed  carcass,  average 

Broilers,  live  weight 

Broilers,  dressed  carcass 

Eggs 


Pounds 

139. 
158.7 
14.8 

6.4 
13.5 
16.8 
12.4 
15. 

8.3 
10.7 

7.6 

8.7 
13.9 
17.8 

7. 

9.6 
30.4 
33. 
25. 
25.7 
63.7 
36.5 
19.6 
19.6 
15.6 
28.7 
23.8 
19.6 


Pounds 
18. 

20.6 
9.4 

5.44 


2.75 
3.56 
2.52 

2.84 


2.60 
3.23 


15.6 
16.1 

8.1 


4.2 

3.5 
5.1 


424  THE  FEEDING  OF  ANIMALS 

It  may  properly  be  said  of  the  foregoing  figures  that 
they  are  only  averages  and  that  the  relation  of  food  to 
production  varies  with  different  animals  of  the  same  class 
and  with  the  conditions  involved.  While  this  is  true,  the 
relations  shown  in  the  preceding  calculations  represent 
differences  too  wide  to  be  explained  on  any  other  ground 
than  that  the  various  animal  products  have  greatly 
unlike  food  cost. 

The  most  noticeable  fact  brought  out  by  this  com- 
parison is  the  low  relative  food  cost  of  milk  and  other 
dairy  products.  The  growth  of  a  pound  of  edible  beef 
solids  requires  a  food  expenditure  nearly  seven  times  as 
great  as  is  necessary  for  the  elaboration  of  a  pound  of 
milk  solids.  On  the  other  hand,  swine  are  fed  with  nearly 
as  great  economy  as  are  milch  cows.  In  fact,  when  proper 
allowance  is  made  for  the  period  of  growth  of  the  cow  and 
for  the  annual  periods  when  she  is  giving  no  milk,  she 
seems  to  have  no  advantage  over  the  pig  except  in  kind 
of  product.  Next,  in  the  order  of  economical  use  of  food, 
comes  the  calf  when  fed  largely  on  milk.  Poultry  prod- 
ucts stand  next  in  line.  Sheep  and  lambs  do  not  differ 
materially  from  steers,  meat  products  of  these  two 
classes  requiring  the  largest  proportional  food  consump- 
tion of  any  form  of  growth  here  considered.  The  order 
of  food  efficiency  as  related  to  the  several  animal  prod- 
ucts is  therefore  as  follows:  milk,  pork,  veal,  poultry 
and  eggs,  mutton,  and  beef. 

It  is  suggestive,  at  least,  to  notice  that  the  food  factor 
is  inversely  as  the  labor  factor  in  these  various  lines  of 
production.  For  instance,  labor  is  a  large  factor  of  the 
cost  of  a  pound  of  any  dairy  product  and  a  small  factor 
in  the  cost  of  beef  or  mutton,  while  the  reverse  is  emphati- 
cally true  of  the  food  cost. 


CHAPTER  XXV 
GENERAL  MANAGEMENT 

THERE  are  many  considerations  pertaining  to  the 
feeding  and  management  of  live-stock  that  have  a  more 
or  less  common  application  to  all  classes  of  animals  and 
which  may  be  discussed  conveniently  under  one  head. 
They  are  partly  of  a  business  character  and  to  quite  an 
extent  lie  outside  the  chemical  and  physiological  princi- 
ples of  nutrition.  Some  of  those  questions  are  matters 
of  much  importance,  but  many  of  them  which  relate,  for 
instance,  to  times  and  methods  of  feeding  are  given  a 
prominence  in  current  discussions  out  of  proportion  to 
their  real  influence  in  determining  success.  It  should 
be  understood,  too,  that  many  of  the  details  of  practice 
are  not  limitable  by  fixed  rules  but  must  be  variable 
according  to  the  conditions  involved.  Tact  and  judgment 
are  demanded  of  the  farmer  who  wisely  adjusts  his 
practice  to  business  principles. 

511.  Factors  in  general  management  of  animals. — 
General  management  properly  includes,  among  other 
considerations,  the  following  topics: 

(1)  The  selection  of  animals;  (2)  manipulation  of 
the  ration  and  manner  of  feeding;  (3)  the  intensity  of 
feeding;  (4)  environment  and  treatment  of  the  animal. 

The  object  to  be  sought  in  feeding  animals  is  the  con- 
version of  a  unit  of  food  into  the  largest  possible  quan- 
tity of  the  product  best  adapted  to  the  producer's  com- 
mercial opportunities,  and  here  the  limitations  of  the 

(425) 


426  THE  FEEDING  OF  ANIMALS 

animal  are  often  the  limitation  of  the  farmer's  profits. 
Within  each  species  varietal  and  individual  differences 
determine  the  rate  of  production  and  also  whether  the 
food  shall  be  transformed  into  poor  milk  or  rich  milk, 
inferior  beef  and  mutton  or  superior  meat  products,  fine 
wool  or  coarse,  trotters  or  draft  horses,  and  small  eggs  or 
large  ones. 

The  selection  of  annuals  should  have  reference  to 
three  general  factors,  which  largely  fix  the  rate  and 
character  of  production,  viz.,  breed,  individuality,  and 
age. 

512.  The  selection  of  cows. — The  breed  and  indi- 
viduality of  the  cow  largely  determine  the  quality  of  her 
product  and  the  quantity  of  production  from  a  unit  of 
food.  Neither  heavy  feeding  nor  skill  in  compounding 
rations  can  be  made  the  means  of  causing  her  to  overstep 
her  constitutional  limitations. 

The  selection  of  cows  simply  with  reference  to  breed 
is  a  question  of  adaptability.  If  the  production  of  milk 
at  the  minimum  food  cost  for  a  unit  of  volume  is  the 
result  most  desired,  the  dairy  breeds  characterized  by 
milk  with  a  low  proportion  of  solids  should  be  chosen; 
but  if  the  object  is  merely  to  secure  butter-fat  with  the 
lowest  possible  food  expenditure,  the  so-called  butter 
breeds  are  in  general  to  be  preferred. 

When  the  chief  consideration  is  the  manufacture  of 
milk  solids  most  economically,  we  must  deal  not  so  much 
with  breeds  as  with  individuals.  In  fact,  with  all  breeds 
and  with  animals  of  no  breed,  individual  capacity  is  the 
consideration  fundamental  to  profitable  feeding.  Some 
Holsteins  will  return  both  more  milk  and  more  butter 
for  a  unit  of  food  cost  than  will  some  Jerseys,  and  the 
reverse  is  equally  true.  There  is  no  magic  in  heredity 


GENERAL  MANAGEMENT  427 

which  overcomes  lack  of  capacity  either  for  the  breeder 
or  for  the  dairyman. 

513.  The    general-purpose    cow. — The    "general-pur- 
pose"  cow  has  been  much  discussed   in  recent  years. 
While  her  specifications  have  never  been  fully  and  clearly 
set  forth,  it  is  supposed  that  she  is  an  animal  reasonably 
profitable  along  both  beef  and  milk  lines.    It  is  doubtful 
whether  such  a  cow,  even  if  she  exists,  is  one  adapted  to 
general  utility.    There  are  few  localities  where  milk  is 
not  more  profitable  than  beef  or  beef  more  profitable 
than  milk,  and  whichever  is  the  more  profitable  should 
be  produced  by  an  animal  of  specialized  capacity.    Any 
extra  value  which  the  calf's  or  the  cow's  carcass  may  have 
when  flesh-forming  tendencies  are  prominent,  will  gen- 
erally come  far  short  of  compensating  for  a  merely  medi- 
ocre milk  yield  in  those  localities  where  there  is  a  market 
for  milk  and  its  products;  and  the  stockman  who  is 
endeavoring  to  put  on  the  market  beef  animals  of  the 
highest  quality  cannot  afford  to  compromise  with  dairy 
qualities.    Milk  formation  and  flesh  formation  are  antag- 
onistic, and  not  correlated,  functions,  both  of  which  do 
not  operate  intensely  in  the  same  individual.   At  present 
we  have  no  breed  or  fixed  type  of  animals  that  can  be 
regarded  as  presenting  and  perpetuating  "general-pur- 
pose" qualities.    Such  a  type,  if  found  at  all,  must  be 
sought  among  individuals. 

514.  The  selection  of  animals  for  meat  production. — 
It  is  generally  conceded  that  the  selection  of  breeds  of  the 
beef  and  mutton  types  is  essential  to  the  highest  success 
in  the  production  of  meat.   This  is  true  with  steers,  not 
because  those  from  the  dairy  breeds  will  make  very 
much  slower  growth  than  Shorthorns  or  Herefords,  for 
this  does  not  seem  to  be  the  fact,  but  because  the  quality 


428  THE  FEEDING  OF  ANIMALS 

of  the  product  is  higher  with  the  latter,  that  is,  the  pro- 
portion of  valuable  parts  is  greater  and  the  distribution  of 
fat  and  lean  tissue  is  more  desirable,  in  the  distinctly 
beef  animal. 

A  choice  from  the  beef  and  mutton  types  and  from 
the  various  breeds  of  swine  may  safely  be  left  to  personal 
preference.  Many  experiments  have  been  conducted 
with  a  view  of  determining  the  relative  capacity  of 
growth  of  the  prominent  breeds  of  bovines,  sheep, 
and  swine,  and  the  testimony  so  far  adduced  is  of  a 
negative  character  and  does  not  point  to  any  one 
breed  of  any  species  as  clearly  superior  to  all  others. 
It  is  well  understood,  however,  that  within  every 
breed  individual  variations  are  important  and  that 
from  a  "bunch"  of  steers  it  is  possible  to  select  some 
animals  superior  to  the  others  in  their  capacity  to  make 
profitable  use  of  food. 

515.  Relation  of  age  to  meat  production. — A  most 
important  factor  in  this  connection  is  the  relation  of  age 
to  the  profits  of  meat  production.  Nothing  has  been  more 
fully  established  by  experimental  evidence  than  that  the 
younger  the  animals  the  larger  the  ratio  of  increase  to 
body  weight  and  the  greater  the  increase  for  each  unit  of 
food  consumed. 

Some  of  the  more  striking  evidence  on  these  points 
is  presented  in  the  following  figures: 

TABLE  XCI 

Results  with  steers  from  five  breeds  slaughtered  at  the  Smithfield 
(England)  Fat-Stock  Show  (from  Henry's  compilation) 

Age  Number  animals  Daily  gain 

One  year  old  77  2.      Ibs. 

Two  years  old  89  1.76    " 

Three  years  old  54  1.58    " 


GENERAL   MANAGEMENT 


429 


TABLE  XCI,  CONTINUED 

Steers  at  American  Fat-Stock  Show  (Stewart's  compilation) 

Age  Number  animals  Daily  gain 

297  days  30  2.6  Ibs 

612     "  152  2.2    " 

943     "  145  1.7    " 

1,283     "  133  1.5    " 

American  experiments  with  pigs  (Henry's  compilation) 

Weight  of  pigs 

38  Ibs. 

78 
128 
174 
227 
271 
320 

Results  of  Danish  experiments  with  pigs. 

Weight  of  pigs  Number  experiments  Food  for  100  Ibs.  gain 

35  to    75  Ibs.  3  376  Ibs. 

75  to  115  10  435 

13  466 


Number  feeding  trials 

Food  for  100  Ibs.  gain 

41 

293  Ibs. 

100 

400 

119 

437 

107 

482 

72 

498 

46 

511 

19 

535    " 

115  to  135 
155  to  195 
195  to  235 
235  to  275 
275  to  315 


15 

14 

11 

3 


513 
540 
614 
639 


Testimony  of  this  character  is  abundant,  and  the  lesson 
for  practice  is  that  animals  should  be  fed  for  market  at 
the  earliest  age  that  is  consistent  with  other  conditions. 

516.  Manipulation  of  the  ration. — A  great  deal  of 
experiment  and  discussion  has  been  devoted  to  the 
economy  of  various  methods  of  treating  cattle  foods, 
such  as  cutting,  grinding,  wetting,  and  cooking.  The 
economy  of  these  operations  requires  no  extended  com- 
ment. It  is  a  simple  and  safe  rule  that  any  fodder  or 
grain,  that  in  its  natural  condition  is  palatable,  is  wholly 
eaten,  and  is  thoroughly  masticated,  should  be  fed  with- 


430  THE  FEEDING  OF  ANIMALS 

out  the  unnecessary  expense  which  these  manipulations 
would  cause.  Grinding  any  material  that  is  not  otherwise 
thoroughly  masticated  doubtless  increases  the  efficiency 
of  the  food,  but  when  the  grinding  costs  as  much  as  10 
per  cent  of  the  market  price  of  the  grain  it  is  doubtful 
if  any  advantage  accrues.  Cutting,  unless  for  the  pur- 
pose of  mixing,  has  the  sole  advantage  of  saving  the  animal 
a  little  work. 

Wetting  and  cooking  render  certain  foods  more 
tender  and  more  palatable,  and  when  this  secures  the 
consumption  of  materials  otherwise  wasted  these  opera- 
tions may  become  economical.  On  the  contrary,  similar 
treatment  of  grain  foods  already  much  liked  by  the 
animal  is,  according  to  the  majority  of  testimony,  an 
occasion  of  loss  rather  than  of  gain. 

Practice  differs  as  to  the  number  of  portions  into 
which  the  daily  ration  shall  be  divided.  Some  herds 
are  fed  three  tunes  a  day  and  some  twice.  While  it 
would  be  possible  to  feed  too  many  times  or  too  much 
at  any  one  time,  it  seems  more  than  probable  that  if 
animals  are  fed  regularly  the  ration  may  be  as  efficient 
when  divided  into  two  portions  as  when  there  are  three 
feeding  periods.  The  adaptation  of  any  system  to  the 
requirements  of  farm  work  is  a  matter  of  more  impor- 
tance, probably,  than  any  influences  proceeding  from  the 
number  of  feeding-periods.  The  warming  of  the  water 
consumed  has  been  introduced  to  some  extent  with  dairy 
herds.  Certainly  it  is  bad  practice  to  force  cows  to  drink 
ice-cold  water,  but  it  is  also  bad  practice  to  warm  the 
water  above  the  point  of  palatableness.  The  likes  and 
dislikes  of  animals  must  be  considered,  and  to  ignore  them, 
even  to  save  the  small  food  expense  necessary  for  warm- 
ing the  ingested  water,  is  not  advisable. 


GENERAL  MANAGEMENT  431 

517.  Quantity  of  the  ration. — Great  stress  is  usually 
laid  upon  the  fact  that  it  is  only  the  food  that  is  supplied 
above   maintenance   needs   which   is   productive.     This 
truth,    indiscriminately    accepted,    has    led    to   feeding 
so  excessively  as  to  injure  the  health  of  the  animals  and 
diminish  profits.    The  largest  production  is  not  always 
the  most  profitable.    Abundant  testimony  can  be  cited 
in  support  of  the  statement  that  very  heavy  rations 
yield  smaller  returns  for   each  unit  of  food  consumed 
than  more  moderate  ones.    It  is  possible,  also,  to  adopt 
an  unprofitable  extreme  in  the  direction  of  light  feeding. 
Heavy  rations   are   sometimes   warranted   by  the   low 
cost  of  feeds  and  the  high  price  of  the  resulting  product, 
a  condition  which  has   not   existed   for   the  past 'ten 
years.  In  the  writer's  judgment,  milk  is  more  economically 
produced  by  cows  not  unusual  in  character  or  size  when 
the  grain  ration,   wisely  compounded,   ranges  between 
eight   and   ten  pounds  daily,  according  to  the  weight 
and  capacity  of  the  animal,  than  when  more  is  fed,  pro- 
vided the  coarse  foods  are  supplied  in  the  ordinary  propor- 
tion.   It  is  especially  important  with  breeding  animals, 
where  the  physical  condition  of  the  dam  should  be  kept 
at  its  best,  that  the  indigestion  and  high  physical  tension 
induced  by  extreme  rations  should  be  avoided.   The  wel- 
fare of  future  generations  demands  this. 

518.  Environment   and   treatment  of  animals. — The 
quarters  in  which  animals  live  should  be  comfortable, 
that  is,  they  should  be  neither  too  warm  nor  too  cold  and 
should  be  well  ventilated.   These  conditions  are  essential 
to   health    and   the   most   profitable   production.     The 
stable  temperature  in  winter  should  be  held  above  45°  F. 
as  a  minimum,  and  may  well  be  kept  below  60°.   A  con- 
stant exchange  of  air  should  be  secured  without  creating 


432  THE  FEEDING  OF  ANIMALS 

cold  drafts,  and  the  "King"  system  of  ventilation  seems 
to  be  worthy  of  commendation. 

All  domestic  animals,  whether  the  milch  cow  or  the 
fattening  steer,  should  have  a  reasonable  amount  of 
exercise  under  comfortable  conditions.  Little  sym- 
pathy should  be  shown  toward  the  modern  fad  of  tying 
cows  by  their  heads  in  one  spot  for  five  or  six  months, 
under  the  plea  that  exercise  is  work  and  work  costs  food. 
The  statement  had  better  be  in  accordance  with  the 
experience  of  all  time,  that  exercise  is  health  and  vigor 
and  that  food  is  well  used  in  maintaining  these.  The  cow 
is  more  than  a  machine;  she  is  a  sentient  being,  suscepti- 
ble to  many  of  the  influences  which  are  essential  to  the 
physical  welfare  of  the  human  species.  Let  no  one  take 
this  opinion  as  an  excuse  for  the  cruel  and  wasteful  expo- 
sure of  farm  animals  to  inclement  weather,  which  is  so 
often  observed,  for  this  is  simply  a  violation  of  the  laws 
of  kindness  and  economy  in  the  other  direction. 

A  sympathetic  relation  should  be  established  between 
the  animal  and  the  herdsman.  Close  observers  declare 
that  such  a  relation  promotes  greater  thrift  and  larger 
production,  especially  with  dairy  cows.  These  animals, 
possessed  of  the  instincts  and  affections  of  motherhood, 
respond  to  fondling  through  its  influence  upon  their 
nervous  organization. 

Moreover,  the  economic  relation  is  not  the  only  one 
man  sustains  to  the  animal  world.  Farm  animals  are 
man's  companions  and  friends  for  which  he  may  enter- 
tain even  sentiments  of  affection.  The  daily  life  of  the 
farm-house  is  full  of  pleasant  experiences  that  belong  to 
the  care  of,  and  association  with,  the  grateful  creatures 
whose  wants  must  be  supplied — the  motherly  cow,  the 
faithful  horse,  or  the  noisy,  cackling  fowl.  No  farmer 


GENERAL  MANAGEMENT  433 

has  reached  his  best  estate  who  does  not  find  in  the 
animal  life  about  him  an  enjoyable  companionship  of 
which  he  need  not  be  ashamed,  and  without  a  sense  of 
which  he  is  not  prepared  to  fulfil  his  obligations  to  the 
creatures  dependent  upon  him. 

619.  Cruelty  to  animals. — While  it  is  the  purpose  of 
this  volume  to  deal  with  the  facts  and  principles  of 
science  and  practice,  it  is  not  improper  briefly  to  urge 
the  need  of  the  cultivation  of  right  sentiment  concerning 
kindness  in  the  care  of  animals,  for  we  really  do  not  fully 
appreciate  the  unkindness  shown  by  man  toward  the 
inferior  species  under  his  control.  In  no  way  has  he  more 
clearly  demonstrated  that  he  partakes  of  the  brute 
nature  than  in  his  treatment  of  the  brute.  As  a  master 
he  has  been  guilty  of  cruelty  which  it  is  humiliating  to 
contemplate,  a  cruelty  not  so  swift  in  its  operation  as 
that  of  the  beast  of  prey,  but  which  is  greatly  more 
shocking  and  is  wholly  at  variance  with  the  exalted 
characteristics  that  we  attribute  to  humanity.  The  half- 
sheltered  animals  that  have  endured  our  cold  northern 
winters — the  spavined,  wind-broken  wrecks  of  our  livery 
stables,  whose  infirmities  secure  for  them  no  relief  from 
hard  service — the  daily  exhibitions  on  our  city  streets  of 
the  patient  draft  horse  with  raw  flesh  under  the  collar 
and  smarting  under  blows  from  unfeeling,  cursing  drivers 
— and  especially  the  deliberately  brutal  practices  of  the 
race-track,  where  amid  the  plaudits  of  a  throng  of  men 
and  women  who  would  claim  to  have  kind  hearts,  noble 
animals,  by  unjustifiable  "scoring"  and  in  the  subse- 
quent race,  are  often  forced  to  the  last  limits  of  endurance 
— these  are  all  evidences  of  an  utterly  selfish  indiffer- 
ence to  the  suffering  of  living  creatures  that  can  neither 
utter  a  complaint  nor  avenge  their  wrongs.  A  certain 
BB 


434  THE  FEEDING  OF  ANIMALS 

proportion  of  humanity  appears  to  regard  the  animal 
as  a  mere  unfeeling  machine  out  of  which  pleasure  and 
gain  are  to  be  forced  even  to  the  pound  of  flesh,  and 
not  as  sentient  beings  capable  of  the  keenest  physical 
pain  and  with  rights  that  should  be  respected.  The 
constant  occurrence  of  the  ill-treatment  of  animals  is 
perhaps  the  cause  of  the  complaisance  with  which  it  is 
regarded,  but  it  is  no  excuse  for  such  thoughtless 
indifference.  Society  notes  and  punishes  flagrant  cases 
of  abuse,  but  the  average  human  conscience  is  not  yet 
sufficiently  tender  toward  man's  treatment  of  his  faith- 
ful servants. 


APPENDIX 

COMPOSITION,  DIGESTION,  AND  FEEDING 
STANDARDS  BY  TABLES 

1.  Average  composition  of  American  feeding-stuffs,  page  435. 

2.  Average  coefficients  of  digestion,  page  441. 

3.  Energy-production  values  of  feeding-stuffs,  page  448. 

4.  Food  standards  for  milk  production  as  developed  by  Haecker, 

Savage,  and  Eckles,  page  455. 

5.  Feeding  standards,  page  457. 

6.  Fertilizing  constituents  of  American  feeding-stuffs,  page  460. 

1.  AVERAGE  COMPOSITION  OF  AMERICAN  FEEDING- 
STUFFS 

The  figures  in  the  following  table  have  been  taken 
from  Bulletin  No.  11,  Office  of  Experiment  Stations; 
Farmers'  Bulletin  No.  22,  United  States  Department  of 
Agriculture;  Bulletin  No.  81,  Vermont  Agricultural 
Experiment  Station,  and  Bulletin  No.  166,  New  York 
Agricultural  Experiment  Station  (Geneva). 

The  percentages  given  represent  averages  from  which 
there  are  material  variations.  These  variations  are 
mostly  due  to  differences  in  the  water-content,  the  in- 
fluence of  locality  and  of  the  stage  of  growth  and  the 
changes  brought  about  by  the  methods  and  conditions 
of  curing.  They  are  not  so  large  and  important  with 
the  grains  as  with  the  fodders. 

A  more  complete  table  of  the  composition  of  feeding- 
stuffs  is  to  be  found  in  Henry  &  Morrison's  "Feeds  and 
Feedings,"  the  edition  of  1915.  The  figures  given  in  the 

(435) 


436 


APPENDIX 


following  tables,  however,  are  sufficiently  full  and  accu- 
rate to  illustrate  the  composition  of  the  various  classes 
of  feeds. 

COMPOSITION  OF  FEEDING-STUFFS 

Nitrogen-  No.  of 

free  analy- 

Water    Ash    Protein    Fiber   extract      Fat      ses 


Green  fodder 
Corn  fodder  —  * 
Flint  varieties  
Flint     varieties     cut 
after    kernels    had 
glazed  

79.8 
77.1 

1.1 
1.1 

2. 
2.1 

4.3 

4.3 

12.1 

14.6 

.7 
8 

40 
10 

Dent  varieties  

79. 

1.2 

1.7 

5.6 

12. 

.5 

63 

Dent     varieties     cut 
after    kernels    had 
glazed  

73.4 

1.5 

2. 

67 

155 

9 

7 

Sweet  varieties  
All  varieties  
Leaves     and     husks, 
cut  green 

79.1 
79.3 

66.2 

1.3 

1.2 

2.9 

1.9 

1.8 

21 

4.4 
5. 

87 

12.8 
12.2 

19 

.5 
.5 

1  i 

21 
126 

4 

Stripped    stalks,    cut 
green  

76.1 

.7 

.5 

73 

149 

5 

4 

Sorghum  fodder  
Rye  fodder  

79.4 
76.6 

1.1 
1.8 

1.3 

2.6 

6.1 

11.6 

11.6 
6.8 

.5 

.6 

11 

7 

Barley  fodder 

79 

1  8 

2  7 

79 

g 

5 

1 

Oat  fodder  

62.2 

2.5 

3.4 

11.2 

19.3 

1.4 

6 

Pasture  grass  

80. 

2. 

3.5 

4. 

9.7 

.8 

Red-top,t  in  bloom  
Tall    oat    grass.J     in 
bloom  
Orchard     grass,     in 
bloom.  . 

65.3 
69.5 
73. 

2.3 
2. 
2. 

2.8 
2.4 
2.6 

11. 
9.4 
8.2 

17.7 
15.8 
13.3 

.9 
.9 
.9 

5 
3 

4 

Meadow     fescue,     in 
bloom  

69.9 

1.8 

2.4 

10.8 

14.3 

.8 

4 

Italian  rye  grass,  com- 
inginto  bloom  
Timothy,§   at   different 
stages       

73.2 
61.6 

2.5 

2.1 

3.1 
3.1 

6.8 
11.8 

13.3 

20.2 

1.3 
1.2 

24 
56 

Kentucky  blue-grass,** 
at  different  stages.  .  .  . 
Hungarian  grass  
Japanese  millet.  .  . 

65.1 
71.1 
75. 

2.8 
1.7 
1.5 

4.1 
3.1 
2.1 

9.1 
9.2 

7.8 

17.6 
14.2 
13.1 

1.3 

.7 
.5 

18 
14 
12 

*Corn  fodder  is  the  entire  plant,  usually  a  thickly  planted  crop.    Corn  stover 
is  what  is  left  after  the  ears  are  harvested. 

tHerd's  grass  of  Pennsylvania.  JMeadow  oat  grass. 

§Herd's  grass  of  New  England  and  New  York.       **June  Grass. 


COMPOSITION  OF  FEEDING-STUFFS 


437 


Water    Ash  Protein 


Green  Fodder — continued 
Red  clover,  at  different 

stages 70.8 

Alsike  clover,*  in  bloom.  74.8 

Crimson  clover 80.9 

Alfalfa.f     at     different 

stages 71.8 

Serradella,   at  different 

stages 79.5 

Cowpea 83.6 

Soja  bean 75.1 

Horse  bean 84.2 

Flat     pea     (Lathyrus 

sylvestris) 66.7 

Rape 84.5 


Nitrogen-  No.  of 

free  analy- 

Fiber    extract      Fat      ses 


2.1 

2. 

1.7 


4.4 
3.9 
3.1 


8.1 
7.4 
5.2 


13.5 
11. 

8.4 


1.1 
.9 

.7 


2.7      4.8        7.4       12.3       1. 


43 
4 
3 

23 


3.2 

2.7 

5.4 

8.6 

.7 

9 

1.7 

2.4 

4.8 

7.1 

.4 

10 

2.6 

4. 

6.7 

10.6 

1. 

27 

1.2 

2.8 

4.9 

6.5 

.4 

2 

2.9 

8.7 

7.9 

12.2 

1.6 

2 

2. 

2.3 

2.6 

8.4 

.5 

2 

Corn  silage  

79.1 

1.4 

1.7 

6. 

11. 

.8 

99 

Sorghum  silage.  

76.1 

1.1 

.8 

6.4 

15.3 

.3 

6 

Red-clover  silage  

72. 

2.6 

4.2 

8.4 

11.6 

1.2 

5 

Soja-bean  silage  

74.2 

2.8 

4.1 

9.7 

6.9 

2.2 

1 

Cowpea-vine  silage  

79.3 

2.9 

2.7 

6. 

7.6 

1.5 

2 

Field-pea-vine  silage..  .  . 

50.1 

3.5 

5.9 

13. 

26. 

1.6 

1 

Silage     of    mixture     of 

cowpea    vines    and 

soja-bean  vines.  .  .  . 

69.8 

4.5 

3.8 

9.5 

11.1 

1.3 

1 

Millet  and  soja  bean.  .  . 

79. 

2.8 

2.8 

7.2 

7.2 

1. 

9 

Corn  and  soja  bean.  .  .  . 

76. 

2.4 

2.5 

7.2 

11.1 

.8 

4 

Rye  

80.8 

1.6 

2.4 

5.8 

9.2 

.3 

1 

Apple  pomace  

85. 

.6 

1.2 

3.3 

8.8 

1.1 

1 

Hay  and  Dry  Coarse  Fodder 
Corn  f  odder,  J  field-cured 
Corn  leaves,  field-cured. 
Corn  husks,  field-cured. 
Corn  stalks,  field-cured. 
Corn  stover  §  field-cured 
Barley  hay,  cut  in  milk. 
Oat  hay,  cut  in  milk.  .  . 
Hay  from — 

Red-top,**  cut  at  dif- 
ferent stages 

Red-top,  cut  in  bloom 

Orchard  grass 

*Swedish  clover. 
fLucerne. 
jEntire  plant. 


42.2 

2.7 

4.5 

14.3 

34.7 

1.6 

35 

30. 

5.5 

6. 

21.4 

35.7 

1.4 

17 

50.9 

1.8 

2.5 

15.8 

28.3 

.7 

16 

68.4 

1.2 

1.9 

11. 

17. 

.5 

15 

40.5 

3.4 

3.8 

19.7 

31.5 

1.1 

60 

15. 

4.2 

8.8 

24.7 

44.9 

2.4 

1 

15. 

5.2 

93 

29.2 

39. 

2.3 

1 

8.9       5.2       7.9       28.6       47.5       1.9  9 

8.7       4.9       8.         29.9       46.4       2.1  3 

9.9       6.         8.1       32.4       41.         2.6         10 

§What  is  left  after  the  ears  are  harvested. 

**Herd's  grass  of  Pennsylvania. 


438 


APPENDIX 

Nitrogen-  No.  of 

free  analy- 

Water    Ash    Protein     Fiber    extract  Fat      ses 


Hay  and  Dry  Coarse  Fodder 
—  continued 

/o 

/o 

70 

70 

70 

70 

Hay  from  —  • 

Timothy,*  all  analy's. 

13.2 

4.4 

5.9 

29. 

45. 

2.5 

68 

Timothy,   cut  in  full 

bloom  

15. 

4.5 

6. 

29.6 

41.9 

3. 

12 

Timothy,  cut  soon  af- 

ter bloom  

14.2 

4.4 

5.7 

28.1 

44.6 

3. 

11 

Timothy,    cut    when 

nearly  ripe  

14.1 

3.9 

5. 

31.1 

43.7 

2.2 

12 

Kentucky  blue-grass.. 

21.2 

6.3 

7.8 

23. 

37.8 

3.9 

10 

Cut  when  seed  was 

in  milk  

24.4 

7. 

6.3 

24.5 

34.2 

3.6 

4 

Cut  when  seed  was 

ripe  

27.8 

6.4 

5.8 

23.8 

33.2 

3. 

4 

Hungarian  grass  

7.7 

6. 

7.5 

27.7 

49. 

2.1 

13 

Meadow  fescue  

20. 

6.8 

7. 

25.9 

38.4 

2.7 

9 

Italian  rye  grass  

8.5 

6.9 

7.5 

30.5 

45. 

1.7 

4 

Perennial  rye  grass.  .  . 

14. 

7.9 

10.1 

25.4 

40.5 

1.7 

4 

Mixed  grasses  

15.3 

5.5 

7.4 

27.2 

42.1 

2.5 

126 

Rowen  (mixed  )t  

16.6 

6.8 

11.6 

22.5 

39.4 

3.1 

23 

Mixed     grasses     and 

clovers  

12.9 

5.5 

10.1 

27.6 

41.3 

2.6 

17 

Swamp  hay  

11.6 

6.7 

7.2 

26.6 

45.9 

2. 

8 

Salt  marsh  

10.4 

7.7 

5.5 

30. 

44.1 

2.4 

10 

Red  clover  

15.3 

6.2 

12.3 

24.8 

38.1 

3.3 

38 

Red  clover  in  bloom.. 

20.8 

6.6 

12.4 

21.9 

33.8 

4.5 

6 

Alsike  clover  

9.7 

8.3 

12.8 

25.6 

40.7 

2.9 

9 

White  clover  

9.7 

8.3 

15.7 

24.1 

39.3 

2.9 

7 

Crimson  clover  

9.6 

8.6 

15.2 

27.2 

36.6 

2.8 

7 

Japan  clover  

11. 

8.5 

13.8 

24. 

39. 

3.7 

2 

Vetch  

11.3 

7.9 

17. 

25.4 

36.1 

2.3 

5 

Serradella  

9.2 

7.2 

15.2 

21.6 

44.2 

2.6 

3 

Alfalfa*  

8.4 

7.4 

14.3 

25. 

42.7 

2.2 

21 

Cowpea  

10.7 

7.5 

16.6 

20.1 

42.2 

2.2 

8 

Soja  bean  

11.3 

7.2 

15.4 

22.3 

38.6 

5.2 

6 

Flat    pea     (Lathyrus 

sylvestris)  

8.4 

7.9 

22.9 

26.2 

31.4 

3.2 

5 

Peanut    vines    (with- 

out nuts)  

7.6 

10.8 

10.7 

23.6 

42.7 

4.6 

6 

Pea  vines  

15. 

6.7 

13.7 

24.7 

37.6 

2.3 

1 

Soja-bean  straw  

10.1 

5.8 

4.6 

40.4 

37.4 

1.7 

4 

Horse-bean  straw  

9.2 

8.7 

8.8 

37.6 

34.3 

1.4 

1 

Wheat  straw  

9.6 

4.2 

3.4 

38.1 

43.4 

1.3 

7 

Rye  straw  

7.1 

3.2 

3. 

38.9 

46.6 

1.2 

7 

Oat  straw  

9.2 

5.1 

4. 

37. 

42.4 

2.3 

12 

Buckwheat  straw  

9.9 

5.5 

5.2 

43. 

35.1 

1.3 

3 

*Herd's  grass'of  New  England  and  New  York.        fSecond  cut.         JLucerne. 


COMPOSITION  OF  FEEDING-STUFFS 


439 


Nitrogen-  No.  of 

free  analy- 

Water    Ash    Protein     Fiber    extract       Fat      ses 


Roots  and  Tubers 
Potatoes 

789 

1 

2  1 

6 

173 

I 

12 

Sweet  potatoes 

71  1 

1 

1  5 

1  3 

247 

4 

6 

Red  beets  
Sugar-beets  
Mangel-wurzels  
Turnips.  .  .  . 

88.5 
86.5 
90.9 
905 

1. 
.9 
1.1 

8 

1.5 
1.8 
1.4 
1  i 

.9 
.9 
.9 
1  2 

8. 
9.8 
5.5 
6  2 

.1 
.1 
.2 

2 

9 
19 
9 
3 

Rutabagas  
Carrots  
Artichokes  

88.6 
88.6 
79.5 

1.2 
1. 
1. 

1.2 
1.1 
2.6 

1.3 
1.3 
.8 

7.5 
7.6 
15.9 

.2 
.4 
.2 

4 
8 
2 

Grains  and  Other  Seeds 
Corn  kernel  — 
Dent,  all  analyses.  .  .  . 
Flint,  all  analyses.  .  .  . 
Sweet,  all  analyses.  .  . 
Pop  varieties. 

10.6 
11.3 

8.8 
107 

1.5 
1.4 
1.9 
1.5 

10.3 
10.5 
11.6 
11.2 

2.2 
1.7 
2.8 
1.8 

70.4 
70.1 
66.8 
696 

5. 
5. 
8.1 
52 

86 
68 
26 

4 

Soft  varieties  
All  varieties  and 
analyses  
Sorghum  seed  
Barley  
Oats  
Rye  

9.3 

10.9 
12.8 
10.9 
11. 
11.6 

1.6 

1.5 
2.1 
2.4 
3. 
1.9 

11.4 

10.5 
9.1 
12.4 
11.8 
10.6 

2. 

2.1 
2.6 
2.7 
9.5 

1.7 

70.2 

69.6 
69.8 
69.8 
59.7 
72.5 

5.5 

5.4 
3.6 

1.8 
5. 
1.7 

5 

208 
10 
10 
30 
6 

Whealr- 
Spring  varieties 

10.4 

1.9 

12.5 

1.8 

71.2 

2.2 

13 

Winter   varieties,    all 
analyses  
All  varieties  
Rice  

10.5 
10.5 
12.4 

1.8 
1.8 
.4 

11.8 
11.9 

7.4 

1.8 
1.8 
.2 

72. 
71.9 
79.2 

2.1 
2.1 
.4 

262 
310 
10 

Buckwheat  
Sunflower  seed  (whole). 
Flaxseed  
Cottonseed  (whole,  with 
hulls)  

12.6 
8.6 
9.2 

10.3 

2. 
2.6 
4.3 

3.5 

10. 
16.3 
22.6 

18.4 

8.7 
29.9 
7.1 

23.2 

64.5 
21.4 
23.2 

24.7 

2.2 

21.2 
33.7 

19.9 

8 
2 
50 

5 

Cottonseed    kernels 
(without  hulls)  .... 
Cottonseed    whole, 
roasted             .    ... 

6.2 
6.1 

4.7 
5.5 

31.2 
16.8 

3.7 
20.4 

17.6 
23.5 

36.6 

27.7 

2 
2 

Peanut    kernels    (with- 
out hulls)  
Horse  bean  
Soja  bean  
Cowpea  

7.5 
11.3 
10.8 
14.8 

2.4 
3.8 
4.7 
3.2 

27.9 
26.6 
34. 
20.8 

7. 
7.2 
4.8 
4.1 

15.6 
50.1 
28.8 
55.7 

39.6 
1. 
16.9 
1.4 

7 
1 
8 
5 

440 


APPENDIX 


Water    Ash    Protein 


Nitrogen-  No.  of 

free  analy- 

Fiber    extract      Fat      ses 


Mitt  Products 

Corn  meal  

15. 

1.4 

9.2 

1.9 

68.7 

3.8 

77 

Corn-and-cob  meal  

15.1 

1.5 

8.5 

6.6 

64.8 

3.5 

7 

Oatmeal  

7.9 

2. 

14.7 

.9 

67.4 

7.1 

6 

Barley  meal  

11.9 

2.6 

10.5 

6.5 

66.3 

2.2 

3 

Rye  flour  

13.1 

.7 

6.7 

.4 

78.3 

.8 

4 

Wheat  flour,  all  analyses 

12.4 

.5 

10.8 

.2 

75. 

1.1 

20 

Buckwheat  flour  

14.6 

1. 

6.9 

.3 

75.8 

1.4 

4 

Ground  linseed  

8.1 

4.7 

21.6 

7.3 

27.9 

30.4 

2 

Pea  meal  

10.5 

2.6 

20.2 

14.4 

51.1 

1.2 

2 

Soja-bean  meal  

10.8 

4.5 

36.7 

4.5 

27.3 

16.2 

1 

Ground  corn  and  oats, 

equal  parts  

13. 

2.2 

10.5 

5.7 

64.2 

4.4 

•  • 

Waste  Products 

Corn  cobs  

10.7 

1.4 

2.4 

30.1 

54.9 

.5 

18 

Hominy  chops  

.11.1 

2.5 

9.8 

3.8 

64.5 

8.3 

12 

Corn  bran  

9.1 

1.3 

9. 

12.7 

62.2 

5.8 

5 

Corn  germ  

10.7 

4. 

9.8 

4.1 

64. 

7.4 

3 

Corn-germ  meal  

8.1 

1.3 

11.1 

9.9 

62.5 

7.1 

6 

Gluten  meal  — 

Cream  

10.1 

.8 

33.7 

1.7 

51.1 

2.6 

Chicago*  .'.... 

12.3 

1.3 

36.5 

1.4 

45.8 

2.7 

King  

7.4 

.5 

33.7 

1.2 

52.6 

4.6 

Gluten  feed  

7.8 

1.1 

24. 

5.3 

51.2 

10.6 

11 

Buffalo*  

9.6 

2.3 

27.1 

6.7 

51.1 

3.2 

Peoria*  

7.5 

.8 

19.8 

8.2 

51.1 

12.6 

1 

Diamond,    or    Rock- 

ford  

8.9 

.8 

23.6 

6.6 

56.6 

3.5 

Chicago  maize  feed  

9.1 

.9 

22.8 

7.6 

52.7 

6.9 

3 

Glucose  feed   and   glu- 

cose refuse  

6.5 

1.1 

20.7 

4.5 

56.8 

10.4 

2 

Dried   starch   feed   and 

sugar  feed  

10.9 

.9 

19.7 

4.7 

54.8 

9. 

4 

Starch  feed,  wet  

65.4 

.3 

6.1 

3.1 

22. 

3.1 

12 

Oat  hulls  

7.3 

6.7 

3.3 

29.7 

52.1 

1. 

.  . 

Oat  feed  

7.7 

3.7 

16. 

6.1 

59.4 

7.1 

4 

Barley  screenings  

12.2 

3.6 

12.3 

7.3 

61.8 

2.8 

2 

Maltsprouts  

5. 

6.4 

27.6 

10.9 

47.1 

3. 

.  . 

Brewers'  grains,  wet  .  .  . 

75.7 

1. 

5.4 

3.8 

12.5 

1.6 

15 

Brewers'  grains,  dried  .  . 

8.2 

3.6 

19.9 

11. 

51.7 

5.6 

3 

Grano  gluten  

5.8 

2.8 

31.1 

12. 

33.4 

14.9 

1 

Rye  bran  

11.6 

3.6 

14.7 

3.5 

63.8 

2.8 

7 

Rye  shorts  

9.3 

5.9 

18. 

5.1 

59.9 

2.8 

1 

Wheat  bran  from  spring 

wheat  

11.5 

5.4 

16.1 

8. 

54.5 

4.5 

10 

"Included 

in  above  average. 

COEFFICIENTS  OF  DIGESTION  441 

Nitrogen-  No.  of 

free  analy- 

Water    Ash    Protein     Fiber    extract  Fat      ses 


fFoste  Products  —  continued 


Wheat  bran  from  winter 
wheat  
Wheat  bran,  all  analyses 
Wheat  middlings  
Wheat  shorts  
Wheat  screenings  
Rice  bran  
Rice  hulls  

12.3 
11.9 
10. 
11.8 
11.6 
9.7 
8.2 

5.9 
5.8 
3.8 
4.6 
2.9 
10. 
13.2 

16. 
15.4 
17.4 
14.9 
12.5 
12.1 
3.6 

8.1 
9. 
5.2 
7.4 
4.9 
9.5 
35.7 

53.7 
53.9 
58. 
56.8 
65.1 
49.9 
38.6 

4. 
4. 
5.6 
4.5 
3. 
8.8 
.7 

7 
88 

12 
10 
5 
3 

Rice  polish                    .  . 

10. 

6.7 

11.7 

6.3 

58. 

7.3 

4 

Buckwheat  hulls  
Buckwheat  bran  
Buckwheat  middlings..  . 
Cottonseed  meal  
Cottonseed  hulls  
Lins'd  meal,  old  proc's. 
Lins'd  meal,  new  proc's 
Peanut  meal  
Peanut  hulls  

13.2 
10.5 
13.2 
6.8 
11.1 
8.3 
10. 
10.7 
9. 

2.2 
3. 
4.8 
6.2 
2.8 
5.3 
5.2 
4.9 
3.4 

4.6 
12.4 
28.9 
45.6 
4.2 
35.7 
36.1 
47.6 
6.6 

43.5 
31.9 
4.1 
5.4 
46.3 
7.5 
8.4 
5.1 
64.3 

35.3 
38.8 
41.9 
25.2 
33.4 
36. 
36.7 
23.7 
15.1 

1.1 
3.3 
7.1 
10.8 
2.2 
7.2 
3.6 
8. 
1.6 

2 
2 
3 

20 

2,480 
5 

Miscellaneous 

Acorns 55.3  1.  2.5  4.4  34.8  1.9 

Apples 80.8  .4  .7  1.2  16.6  .4 

Apple  pomace 76.7  .5  1.4  3.9  16.2  1.3          7 

Beet  pulp 89.8  .6  .9  2.4  6.3  ..         16 

Beet  molasses 20.8  10.6  9.1  .  .  59.5  .  .         35 

Cabbage 90.5  1.4  2.4  1.5  3.9  .4          2 

Prickly  comfrey 88.4  2.2  2.4  1.6  5.1  .3         41 

Pumpkin  (field) 90.9  .5  1.3  1.7  5.2  .4 

Sugar-beet  leaves 88.  2.4  2.6  2.2  4.4  .4 


2.  AVERAGE  COEFFICIENTS  OF  DIGESTION 

The  coefficients  of  digestion  which  follow  are  mostly 
taken  from  the  compilation  by  Jordan  and  Hall  as  pub- 
lished in  Bulletin  No.  77,  Office  of  Experiment  Stations. 
Others,  marked  G,  are  from  the  compilation  of  Dietrich 
and  Konig  ("Composition  and  Digestibility  of  Cattle 
Foods,"  Vol.  II).  Later  figures  are  found  hi  Report  of 
Hatch  Experiment  Station,  Massachusetts,  1905,  and  in 
Henry  &  Morrison's  "Feeds  and  Feeding,"  1915. 


442  APPENDIX 


DIGESTION  BY  RUMINANTS 

i  Digestion  coefficients 


Nitrogen- 
No,  ex-  Kind  and  condi-  Dry  Organic  Pro-  free  ex- 
perim'ts  tion  of  food  matter  matter  Ash  tein  Fiber  tract  Fat 

%  %  %  %  %  %  % 
GREEN  FODDERS 

Meadow  Grasses 

3  .  Hungarian 67.2  68.6  52.2  64.3  71.2  67.9  65.7 

4  .  Barnyard  millet 66.6  67.  59.5  61.5  66.5  68.3  64.3 

1  .  Timothy 63.5  65.6  32.2  48.1  55.6  65.7  53.1 

1  .  Timothy  rowen 64.8  66.4  45.2  71.7  63.8  67.8  52.9 

1  .  Pasture  grass 68.7  70.  49.7  65.5  74.3  72.5  54.7 

1  .  Mixed-grass  rowen 65.6  67.4  46.2  67.4  62.6  71.6  55.2 

Cereal  Plants 

2  .  Barley 65.9  67.5  54.4  71.8  60.8  71.2  59.9 

8  .  Dent  corn,  immature.  .      68.8  70.7  45.4  65.2  66.6  73.  72. 

6  .  Dent  corn,  mature 66.6  68.5  19.4  52.3  51.6  74.7  77. 

14  .  Dent  corn,  all  samples..     67.8  69.8  35.6  59.7  60.2  73.7  74.1 

6  .  Sweet  corn 71.1  72.2  55.3  64.  62.9  76.6  75.6 

3  .  Oats 59.5  60.9  53.4  71.8  52.8  62.6  69.2 

1  .  Rye 73.4  75.3  55.8  79.4  79.2  70.1  74.5 

2  .  Sorghum 67.3  69.  42.4  46.8  59.  74.6  74.2 

Clovers  and  Legumes 

6.  Alfalfa  (G) 64.  ..81.  41.  72.  45. 

1  .  Crimson  clover 67.9  69.1  56.1  77.1  56.1  74.5  66.5 

1  .  Red  clover 66.1  68.1  55.  67.  52.6  77.6  64.5 

1  .  Red     clover,     before 

bloom  (G) 74.  .  .  74.  60.  83.  65. 

2  .  Red    clover,    beginning 

bloom  (G) 71.  .  .  74.  57.  79.  71. 

2  .  Red  clover,  bloom  to 

end  (G) 61.  ..64.  44.  71.  53. 

1  .  Red-clover  rowen '.  59.3  60.8  43.4  61.9  52.5  65.3  60.8 

1  .  Canada  peas 68.4  71.3  42.3  82.  62.4  71.  52.4 

2  .  Cowpea 68.3  74.1  22.8  75.6  59.6  80.6  59.4 

4.  Soybean 59.8  64.5  18.9  75.1  47.  73.2  54.1 

1  .  Common  vetch 61.8  65.7  17.3  71.4  44.2  76.1  58.6 

3.  Hairy  vetch 70.3  73.1  45.1  82.8  61.1  76.3  71.6 

Mixed 

1  .  Barley  and  peas 53.4  60.2  46.2  77.2  43.5  61.4  59.7 

4  .  Oats  and  peas 65.4  67.2  45.4  76.1  59.7  67.7  67.7 

1  .  Vetch  and  oats. . .              67.  68.4  52.7  74.8  68.3  67.9  47.2 


COEFFICIENTS  OF  DIGESTION  443 


-Digestion  coefficients 


No.  ex-        Kind  and  condi-  Dry  Organic                Pro-  ireeex- 

penm  ts          tion  of  food  matter  matter  Ash       tein  Fiber  tract      Fat 

S.LAOB 

Maize 

9.  Dent  corn 65.1  '67.1  32.2  49.3  667  686  80 

6.  Flint  corn 73.1  76.1  32.9  62.8  75.1  76*9  81*8 

L3  .  Dent  corn,  immature. .  65.6  67.4  34.3  51.3  706  674  80*2 
10  .  Dent    and    flint    corn, 

mature 70.8  73.6  30.3  56.  70.  76 1  82  4 

1  .  Sweet  corn 68.1  70.1  31.9  54.  71.1  71.8  83^5 

Miscellaneous 

1  .  Cowpea 59.6  63.4  30.3  57.5  52.  72.5  62.6 

1  .  Soybean  (steers) 49.8  53.8  28.  55.3  42.9  61.2  48.9 

1  .  Soybean  (goats) 59.  59.3  56.7  75.7  54.8  52.  71.9 

1  .  Corn  and  soybean 69.  71.  ..  65.  64.8  74.9  82.1 

1  .  Millet  and  soybean....  58.8  59.9  ..  58.4  69.4  59.2  72.2 
1  .  Corn,  horse  beans,  and 

sunflower  heads 65.6  67.8  41.1  62.7  60.1  72.4  76.7 

1  .  Corn,  horse  beans,  and 

sunflower  plants. ..  .  65.5  69.3  25.6  58.  65.3  73.7  74.1 

DRIED  FODDERS 

Meadow  Grasses 

1  .  Black     grass      (Juncus 

bulbosus) 59.5  .  .  .  .  63.  60.5  57.  41.5 

1  .  Black     grass     (Juncus 

Gerardii) 53.4  52.1  69.  54.3  57.4  49.  45.7 

2  .  Blue  joint 54.3  55.8  29.4  63.4  54.5  55.9  44.7 

1  .  Branch     grass      (Spar- 
tina stricta  glabra) ...  56 62.5  52.  54.  32. 

1  .  Branch  grass  (Distichlis 

spicata) 49.7  48.9  58.1  51.7  56.4  45.7  36.6 

1  .  Chess  or  cheat 45.  47.3  23.  42.  46.  49.  32. 

2  .  Crab  grass 53.6  55.  37.6      .  .  59.1  54.5  46.8 

1  .  Fox     grass      (Spartina 

patens) 54.8  54.5  58.2  59.3  57.4  53.1  36.4 

1  .  Fox     grass      (Spartina 

juncea,  etc.) 53 57.  51.  52.  24. 

1  .  Flat  sage 56.1  57.3  62.  51.8  60.4  55.1  36.1 

1  .  Hungarian  grass 65.  66.3  47.4  60.  67.6  67.1  63.9 

2  .  Johnson  grass 56.5  58.3  30.5  41.4  65.7  56.9  38.4 

1  .  Barnyard  millet 57.4  56.8  63.1  63.7  61.6  51.6  46.3 

1  .  Cat-tail  millet 62.3  61.6  68.4  62.6  66.5  59.1  46.1 

2  .  Orchard  grass 56.6  57.8  .  .  59.5  60.4  55.4  53.8 

2  .  Red-top 59.7  61.2  29.  61.3  61.3  61.9  50.5 

1  .  Red-top  and  sedge 46.  48.5  10 1  37.2  55.7  45.6  49. 

17  .  Timothy 56.5  57.9  32.8  46.9  52.5  62.3  52.2 


444  APPENDIX 


Digestion  coefficients  — - 


Nitrogen- 
No,  ex-        Kind  and  condi-            Dry  Organic  Pro-  free  ex- 
perim'ts          tion  of  food             matter  matter  Ash  tein  Fiber  tract  Fat 

%  %  %  %  %  %         % 
Meadow  Grasses — continued 

3  .  Timothy,   before  or  in 

bloom 60.7.61.5  44.2  56.8  58.8  64.3  58.4 

4  .  Timothy,  past  bloom ..      53.4  54.5  30.3  45.1  47.1  60.4  51.9 

1  .  Timothy  rowen 62.2  64.4  56.4  68.  66.5  63.4  49.5 

2  .  Wild-oat  grass 64.  65.2  34.7  58.3  67.9  65.5  50.5 

2.  Witch  grass 61.2  62.3  40.9  58.6  62.8  65.6  57.2 

1  .  Black    grass    and    red- 

top  (cove  mixture).. .     54.6  54.3  57.5  47.9  59.7  53.2  40.3 

5  .  Mixed  grasses 57.1  58.8  .  .  58.5  59.7  58.7  48.5 

Meadow  hay — 

Best  (G) 67.    .  V.  '  65.  63.  68.  57. 

Medium  (G) 61.  .v  67.  60.  64.  53. 

Poor  (G) 56.  .  .  50.  56.  59.  49. 

2  .  Pasture  grass 72.6  73.2  51.8  73.4  76.1  74.2  67.3 

1  .  Swale  hay 39 34.  33.  46.  44. 

1  .  High-grown  salt  hay. .  .     53 63.  50.  53.  47. 

1  .  Salt-hay  mixture 56.4  54.9  69.8  42.6  60.7  54.7  29.7 

2  .  Rowen  hay 64.4  65.8  46.6  69.1  66.6  66.2  47.4 

Cereal  Plants 

1  .  Barley  hay 61.2  62.3  44.8  65.2  61.7  63  3  40. 

17  .  Dent  corn  fodder. :.....      64.3  66.1  30.7  50.4  62.2  68.  73.6 

7  .  Flint  corn  fodder 68.6  71.7  42.6  60.  74.9  70.3  71.4 

13  .  Dent  and  flint  corn 

fodders  (immature). .  63.9  65.7  37.2  51.7  66.  66.2  72.2 
10  .  Dent  and  flint  corn 

fodders  (mature) ....     68.2  70.7  30.6  56.1  65.8  72.2  73.9 

3  .  Sweet  corn  fodder 67.2  69.8  35.6  64.1  73.8  68.2  73.6 

5  .  Corn  stover 57.2  59.1  32.6  35.9  64.2  57.9  70.4 

3  .  New  corn  product 58.1  59.2  38.7  46.7  57.  60.5  78.2 

2  .  Topped  corn  fodder. . . .     57.4  62.3  3.8  38.7  71.  57.9  67.4 

1  .  Corn  blades  and  husks.     63.8  67.1  22.6  47.7  72.9  66.4  58.1 

2  .  Corn     leaves     (pulled 

fodder) 59.8  63.6  26.8  48.4  67.5  63.  59.9 

1  .  Corn  husks 72.  74.2  16.  29.5  79.5  75.  32.5 

1  .  Corn  butts 66.5  69.4  11.5  21.  73.5  69.  79.5 

1  .  Oat  hay 49.3  50.1  34.6  54.2  43.5  52.  61.9 

1  .  Oat  straw 50.3  52 57.6  53.2  38.3 

Bean  straw 55.  .  .  49.  43.  67.  57. 

Wheat  straw  (G) 46.  ..  23.  55.  39.  36. 

Rye  straw  (G)'. 48.  .  .  25.  63.  39.  29. 

Barley  straw  (G) 53.  .  .  25.  55.  54.  42. 

Rice  straw  (G) 47.  ..  45.  57  32.  47. 

1  .  Sorghum  fodder  (pulled)    63.1  64.8  29.5  60.8  70.4  64.5  46.7 

1  .  Sorghum  bagasse 60.6  62.2  13.4  13.7  63.8  64.8  46.4 


COEFFICIENTS   OF  DIGESTION 


445 


Digestion  coefficients  • 


No.  ex- 
perim'ts 


Kind  and  condi- 
tion  of  food 


Dry  Organic 
matter  matter    Ash 


Nitrogen- 
Pro-  free  ex- 
tein     Fiber    tract      Fat 


Clovers 

2  .  Alsike  clover 

4  .  Crimson  clover 

6  .  Red  clover 

2  .  Red-clover  rowen. . . . 
1  .  White  clover. . . 


62.3  63.2  52.2  66.1  53.5  70.7  50.2 
58.1  59.1  51.9  68.7  46.7  64.6  43,4 

57.4  59.7  29.1  58.  54.2  64.4  55.2 
58.  59.1  45.8  64.8  47.4  62.8  59.8 
66.  66.6  58.5  73.2  60.6  69.5  50.6 


Legumes  Other  Than  Clovers 

3  .  Alfalfa 58.9 

1  .  Cowpea  vine 59.2 

1  .  Peanut  vine -.  .  .     59.9 

1  .  Soybean 62.4 

1.  Hairy  vetch 69.4 

Bean  straw  (G) 

Pea  straw,  good  (G) 

Miscellaneous  and  Mixed 

1  .  Buttercup  hay 56.1 

1  .  Whiteweed  hay 57.8 

2  .  Clover  and  timothy. ...  54.6 


60.7  39.5  72.  46.  69.2  51. 
60.  49.5  64.8  42.  70.6  51.8 
63.1  20.4  63.3  51.9  69.5  65.9 
63.9  .  .  71.1  60.8  68.8  29.2 

71.8  42.2  82.3  61.1  72.9  70.3 
55.  .  .  49.  43.  67.  57. 


59. 


60.       52.       64.       46. 


56.6    48.1     56.3     41.1     66.9     69.7 
58.3     52.       58.4    45.5     66.7    62. 
53.2      .  .      42.3     49.6     57.5     54. 


Grains  and  Seeds 
Barley  (G) 

86. 

70. 

92 

89 

Oats  (G) 

71. 

78. 

26. 

77. 

83. 

5  . 
2  . 

Corn  meal  
Corn-and-cob  meal  .... 
Rye  meal  
Pea  meal 

89.4 
78.7 
87.3 
86.8 

89.6  .  . 
79.8  .  . 
88.7  .  . 
87.9  43.7 

67.9 
55.6 

84.4 
83.2 

45.7 
25.7 

94.6 
87.6 
91.9 
93.6 

92.1 
84.1 
64.2 
54.5 

Field  beans 

89. 

88. 

72. 

92. 

81. 

Soybean  meal  
Cottonseed,  raw  
Cottonseed,  roasted.  .  .  . 
Linseed 

81.9 
66.1 
55.9 

84. 
65.8    43.3 
56.8      .  . 

77. 

91.1 
67.8 
46.9 
91. 

71.2 
75.5 
65.9 
60. 

76.3 
49.6 
51.4 
55. 

85.7 
87.1 
71.7 
86 

Acorns  .  .  .  .  . 

88. 

83. 

62. 

91. 

87. 

1  . 
1  . 

2  . 
1  . 
5  . 
4  . 
1  . 

BY-PRODUCTS 
Cereals 
Atlas  meal  
Cerealine  feed  
Corn  cobs  
Dried  brewers'  grains.  . 
Gluten  feed  
Gluten  meal  
H.  O.  dairy  feed  

79.6 
90.4 
51.4 
61.6 
86.3 
89.7 
65.3 

83.4  .  . 
92.7  .  . 

65.4  !  '. 
87.3  .  . 
90.4  .  . 
68. 

72.8 
76.6 
19.3 
79.3 
85.6 
88.2 
77.8 

105.7 
82.2 
57.5 
52.6 

78. 

40.8 

84.5 
95.3 
48.3 
57.8 
89.2 
89.8 
69.9 

91.2 
80.6 

Ql.'l 

84.4 
94.4 
85.5 

446 


APPENDIX 


Digestion  coefficients  • 


No.  ex- 
perim'ts 


Kind  and  condi- 
tion of  food 


Dry  Organic 
matter  matter    Ash 


Cereals — continued 

1  .  H.  O.  horse  feed 70.1  72.6  .. 

1.  Maize  feed 87.1  87.1  .. 

1  .  Maltsprouts 67.1  67.2  .  . 

1  .  Quaker  oat  feed 62.  65.3  .. 

1  .  Victor     corn  -  and  -  oat 

feed 74.7  77.4  .. 

7.  Wheat  bran 62.3  65.7  .. 

1  .  Wheat  bran  and  shorts.  60.2  60.7  7.5 

3  .  Wheat  middlings 75.  78.5  .  . 


Nitrogen- 
Pro-  free  ex- 
tein  Fiber  tract  Fat 


74.4  35.2  78.7  84. 

85.5  82.5  87.9  91.5 
80.2  32.9  68.1  104.6 
81.1  42.6  67.4  89. 

70.8  48.3  83.  86.8 

77.8  28.6  69.4  68. 

75.8  18.3  64.3  45. 

79.8  33.1  81.3  86.3 


Oil-bearing  Seeds 

3  .  Cottonseed  hulls 39.8     40.5     23.2      .  .      40.       41.1     85.7 

5  .  Cottonseed  meal 73.7     76.1     23.7     88.4     55.5     60.6     93.3 

1  .  Linseed  meal,  old  pro- 

cess      78.7     81.2      .  .      88.8     57.       77.6     88.6 

2  .  Linseed  meal,  new  pro- 

cess      79.2     81.8      ..      85.2     80.4     86.1     96.6 


Miscellaneous 

1  .  Peanut  feed 

1  .  Rice  meal 


32.1     32.8 
73.8     81.6 


70.6     11.7     49.1     89.7 
61.9  92.3     91.1 


ROOTS 

1  .  Mangolds 

1  .  Potatoes,  raw 

1  .  Potatoes,  boiled 

1  .  Rutabagas 

1  .  Sugar-beets 

1  .  Turnips 


78.5  84.8  16.4  74.7    42.8  91.3 

75.7  77.  .  .  44.7      .  .  90.4  13. 

80.1  81.2  .  .  43.4      .  .  92.1 

87.2  91.1  31.2  80.3     74.2  94.7  84.2 
94.5  98.7  31.9  91.3  100.7  99.9  49.9 

92.8  96.1  58.6  89.7  103.  96.5  87.5 


ANIMAL  PRODUCTS 

Cow's  milk  (G) 98.        .         94.        .  .      98.  100. 

Meat  meal  (G) 93.        .  .      96.        .  .        .  .  99. 

Dried  blood  (G) 63.        ..62.        ..     100.  100. 

Dried  fish,  ground  (G) 90 76. 


DIGESTION  BY  HORSES 

Dried  Fodders 
2  .  Timothy    hay    in    full 

bloom,  well  cured. ...     43.5     44.1     34.       21.2     42.6    47.3     47.3 
2  .  New  corn  product 49.9     51.7     21.7     67.5     54.6    46.9     59.8 


COEFFICIENTS   OF  DIGESTION  447 


fo.  ex-       Kind  and  condi- 
lerim'ts          tion  of  food            : 

Dried  Fodders  —  continued 
Meadow  hay  — 
Best  (G)  
Medium  (G)  
Poor  rm 

Dry  Organic 
matter  matter 

%          % 

.  .      58. 
.  .      50. 
.  .      46. 
..      51. 
.  .      58. 
.  .      21. 

93 

Pro- 
Ash        tein 

%           % 

.  .      63. 
.  .      57. 
.  .      55. 
.  .      56. 
.  .      73. 
,  .      28. 

88 

I 

Fiber 

% 

48. 
39. 
38. 
37. 
40. 
18. 

"Jitrogen- 
free  ex- 
tract     Fat 

%          % 

65.       22. 
58.       18. 
52.       24. 
63.       29. 
70.       14. 
28.       66. 

99. 
94. 

75.       71. 
87.       42. 
92.       61. 
94.       13. 

89.         7. 
88.2    47.7 

95.7     73.1 
79.4    82.4 
86.1     79.9 

2. 
2. 

2  . 
2. 

Red-clover  hay  (G)  
Alfalfa  hay  (G)  
Wheat  straw  (G)  

Roots 
Potatoes  (G) 

Carrots  (G) 

87. 

99. 

Grains 
Oats  (G)  
Barley  (G)  
Corn  (G) 

.  .      69. 
.  .      87. 
89. 

.  .      79. 
.  .      80. 
76 

29. 

40.' 
65. 

8. 
(?) 

(?) 
31.1 
14.4 

Field  beans  (G)  
Peas  (G)  
Dent  corn,  unground... 
Corn  meal,   same  ma- 
terial, ground     ...    . 

.  .      87. 
.  .      80. 
74.4     75.3 

88.4      .  . 
72.4    74.1 
75.7     77.7 

.  .      86. 
.  .      83. 
26.3     57.8 

.  .      75.6 
33.1     86.1 
29.2     82.4 

White  oats,  first  qual- 
ity, unground  

Oats,     same    material, 
around  .  . 

DIGESTION  BY  SWINE 
Grains  and  Seeds 

1  .  Barley,  whole  kernel..  80.1  80.3  6.4     81.4  48.7  86.6    57. 

1  .  Flint  corn,  unground  .  89.7  91.3  .  .     89.9  48.7  93.9    77.6 

1  .  Corn  meal,  same  mate- 
rial, finely  ground ..  89.5  91.2  ..  86.1  29.4  94.2  81.7 

1  .  Corn -and -cob  meal, 

whole  ear  ground  . .  75.6  76.7  .  .  75.7  28.5  83.6  82. 

?  .  Wheat,  unground 72.  .  .  44.       70.  30.  74.       60. 

?  .  Wheat,  cracked 82.  .  .  50.       80.  60.  83.       70. 

1  .  Peas,  ground 89.8  91.5  40.3     88.6  77.9  95.1     50. 

By-products 

1 .  Wheat  bran 65.8  .  .  .  .      75.1  33.  65.5     71.8 

Rye  bran  (G) 67.  .  .      66.         9.  74.       58. 

2 .  Wheat  shorts 76.5  .  .  5.4    73.5  36.5  86.8 

2.  Linseed  meal.  .          .  .,  77.5  ..  10.       86.  12.  85.       80. 


448  APPENDIX 

, '• Digestion  coefficients N 

Nitrogen- 
No,  ex-  Kind  and  condi-  Dry  Organic  Pro-  free  ex- 
perim'ts  tion  of  food  matter  matter  Ash  tein  Fiber  tract  Fat 

%  %         %  %         %          %          % 

Roots 

2  .  Potatoes,  raw 97.         .  .       44.6     84.5       .  .       98.1 

2  .  Potatoes,  cooked 95.         ..      40.       82.         ..       97.6 

Animal  Products 

Meat  meal  (G) 92.  .  .  97 86. 

Dried  blood  (G) .  .  73.  .  .  72.         .         92. 

Sour  milk  (G) 95.  .  .  96.         .  .      98.       95. 

3.  COMPUTATION   OF  ENERGY-PRODUCTION  VALUES 
(TO   THE    100  POUNDS) 

The  following  remarks  and  tables  are  by  Armsby  and 
Putney  (Pennsylvania  Experiment  Station,  Bulletin  No. 
142),  who  write:  "It  is  obviously  impracticable  to  apply 
the  laborious  methods  of  respiration  and  calorimeter 
experiments  to  all  the  great  variety  of  feeding-stuffs  now 
in  use.  It  does  appear  possible,  however,  to  select  a  few 
typical  representatives  of  the  different  classes  and  to  apply 
the  results  obtained  upon  them  to  other  similar  materials, 
much  as  is  even  yet  done  to  a  considerable  extent  with  the 
results  of  digestion  experiments.  The  somewhat  compli- 
cated method  used  by  Kellner  for  this  purpose  has 
already  been  described  in  Bulletin  No.  71  of  this  Station 
as  well  as  in  Kellner's  smaller  textbook,  of  which  an 
English  translation  entitled  The  Scientific  Feeding  of 
Farm  Animals'  has  lately  been  published.  (Kellner 
expresses  the  results  in  terms  of  so-called  'starch  values,' 
which  are  really  energy  values  and  can  equally  well  be 
expressed  in  Therms.)  A  simpler  method,  however,  can 
be  used.  Extensive  tables  are  available  which  show  with 
more  or  less  accuracy  for  a  large  number  of  feeding-stuffs 
the  digestible  nutrients,  the  sum  of  which,  of  course,  makes 
up  the  total  digestible  organic  matter." 


ENERGY-PRODUCTION   VALUES  449 

As  an  illustration  of  the  method  of  computation  we 
may  take  average  timothy  hay,  containing  the  following 
amounts  of  digestible  matter: 

IN  100  POUNDS  OF  TIMOTHY  HAY 

Pounds 

Dry  matter 88.4 

Digestible 

Protein 3. 

Carbohydrates 42.8 

Fat 1.2 

Total  digestible  organic  matter 47. 

According  to  previous  figures,  each  pound  of  digestible 
organic  matter  in  roughage  contains  approximately  1.588 
Therms  of  metabolizable  energy,  while  Table  1  shows 
that  each  pound  of  dry  matter  of  timothy  hay  causes  a 
heat  expenditure  of  0.3547  Therms.  The  net  energy  value, 
therefore,  of  the  88.4  pounds  of  dry  matter  contained  in 
100  pounds  of  the  hay  would  be : 

Metabolizable  energy . .  1.588  Therms  x  47.0=74.64  Therms 
Heat  expenditure 0.3547  Therms  x  88.4=31.36  Therms 

Net  energy  value 43.28  Therms 

Continuing,  Armsby  and  Putney  discuss  the  net  energy 
values  of  American  feeding-stuffs  as  follows: 

"Henry  and  Morrison  ('Feeds  and  Feeding,'  15th 
edition,  pages  633-66)  have  recently  published  a  very 
valuable  compilation  of  American  analyses  of  feeding- 
stuffs  and  of  the  results  of  American  digestion  experi- 
ments, and  on  this  basis  have  calculated  the  content  of 
digestible  nutrients  (for  ruminants)  in  a  great  variety  of 
feeding-stuffs. 

"With  the  permission  of  these  authors,  we  have  under- 
taken to  compute  from  their  tables  the  net  energy  values 
of  the  more  important  feeding-stuffs  in  the  manner  illus- 
cc 


450  APPENDIX 

trated  in  the  last  paragraph  of  the  foregoing  paper  and 
with  the  results  contained  in  the  following  table,  which 
includes  also  the  digestible  (true)  protein  and  the  non- 
protein.  In  regard  to  this  table  it  is  to  be  remarked: 

"First,  both  the  digestion  coefficients  used  by  Henry 
and  Morrison  and  the  data  for  the  expenditure  of  energy 
due  to  feed  consumption  are  derived  exclusively  from 
experiments  on  ruminants  (in  the  latter  case,  on  cattle). 
Consequently,  the  net  energy  values  here  computed  are  ap- 
plicable to  ruminants  only  and  not  to  horses  nor  to  swine. 

"Second,  the  table  shows  primarily  the  net  energy 
values  for  maintenance  or  fattening.  There  seems  good 
reasons  for  believing,  however,  that  they  may  be  taken 
without  serious  error  to  represent  also  the  net  energy 
values  for  growth  and  at  least  the  relative  values  for 
milk  production. 

"Third,  in  comparing  the  figures  for  the  various  feed- 
ing-stuffs, account  should  be  taken  of  the  differences  in 
moisture-content.  Many  of  Henry  and  Morrison's 
averages  for  dry  feeds  show  a  remarkably  low  moisture- 
content,  tending  to  raise  the  suspicion  that  some  of  the 
analyses  averaged  were  made  on  partially  dried  samples, 
although  the  authors  state  that  every  precaution  was 
taken  to  exclude  such  cases  from  the  compilation.  It  is 
evident  at  least  that  more  study  of  the  actual  percentage 
of  moisture  in  feeding-stuffs  as  they  are  used  in  practice 
is  much  to  be  desired. 

"Fourth,  Henry  and  Morrison's  tables  include  only  the 
crude  protein  (N  X  6.25).  The  amount  of  non-protein 
has  been  estimated  from  the  crude  protein  by  the  writers 
on  the  basis  of  Kellner's  averages." 

In  accordance  with  the  method  and  data  mentioned 
the  following  table  was  calculated : 


ENERGY-PRODUCTION   VALUES 


451 


AVERAGE  DRY   MATTER,   DIGESTIBLE 
TRUE   PROTEIN,  AND   NET  ENERGY 

FOR  RUMINANTS: 


DRIED  ROUGHAGE 
Hay  and  Fodder  from  Cereals 

Brome  grass,  smooth 

Corn  fodder  (ears  included,  medium  dry) 
Corn  stover  (ears  removed,  medium  dry) 

Millet,  Hungarian 

Mixed  timothy  and  clover 

Oat  Hay 

Orchard  grass 

Red  top 

Timothy,  all  analyses 

Timothy,  before  bloom 

Timothy,  early  to  full  bloom 

Timothy,  late  bloom  to  early  seed 

Timothy,  nearly  ripe 


Hay  and  Fodder  from  Legumes 

Alfalfa,  aU  analyses 91.4 

Alfalfa,  before  bloom 93.8 

Alfalfa,  in  bloom 92.5 

Alfalfa,  in  seed 89.6 

Clover,  alsike 87.7 

Clover,  crimson 89.4 

Clover,  red,  all  analyses 87.1 

Clover,  red,  before  bloom 89.6 

Clover,  red,  in  bloom 86.1 

Clover,  red,  after  bloom 77.9 

Clover,  sweet,  white 91.4 

Cowpeas,  all  analyses 90.3 

Cowpeas,  before  bloom 92.2 

Cowpeas,  in  bloom  to  early  pod 89.4 

Soybeans 91.4 

Straws 

Barley 85.8 

Buckwheat 90.1 

Oat 88.5 

Rye 92.9 

Wheat 91.6 


CRUDE  PROTEIN,   DIGESTIBLE 
VALUES  TO  THE   100  POUNDS 

. Digestible >     Net 

Dry  Crude  True  energy 
matter  protein  protein  value 
Pounds  Pounds  Pounds  Therms 


91.5 

5. 

3.5 

40.83 

81.7 

3. 

2.3 

43.94 

81. 

2.1 

1.6 

31.62 

85.7 

5. 

3.9 

46.96 

87.8 

5.3 

3.2 

41.07 

88. 

4.5 

3.9 

32.25 

88.4 

4.7 

3.3 

44.93 

90.2 

4.6 

3.9 

51.22 

88.4 

3. 

2.2 

43.02 

92.8 

4.7 

2.9 

43.52 

87.2 

3.6 

2.5 

47.4 

85.1 

2.4 

1.8 

37.54 

87.5 

2.2 

1.8 

38.59 

10.6 

7.1 

34.23 

15.4 

10.3 

36.23 

10.5 

6.7 

32.33 

8.5 

6.2 

32.23 

7.9 

5.3 

34.42 

9.7 

6.9 

36.21 

7.6 

4.9 

38.68 

11.6 

5.4 

42.17 

8.1 

5.3 

39.12 

6.8 

4.5 

34.51 

10.9 

6.7 

38.98 

13.1 

9.2 

37.59 

17.8 

12.8 

33.54 

12.6 

9.5 

39.11 

11.7 

8.8 

44.03 

.9 

4.2 
1. 

.7 
.7 


.6 
3.2 
.8 
.5 
.3 


36.61 

4.55 

34.81 

17.59 

7.22 


452 


APPENDIX 


FRESH  GREEN  ROUGHAGE 


, Digestible ,     Net 

Dry  Crude  True  energy 
matter  protein  protein  value 
Pounds  Pounds  Pounds  Therms 


Green  Cereals,  Etc. 

Barley  fodder  

23.2 

2.3 

2. 

14.08 

Blue-grass,  Kentucky,  before  heading... 

23.8 

3.7 

2.8 

14.82 

Blue-grass,  Kentucky,  headed  out  

36.4 

2.8 

2.2 

17.77 

Blue-grass,  Kentucky,  after  bloom  

43.6 

1.9 

1.6 

21.01 

Buckwheat,  Japanese  

36.6 

2.2 

1.5 

17.78 

Cabbage  

8.9 

1.9 

1.3 

8.87 

Cabbage,  waste  outer  leaves  

14.1 

1.7 

1.1 

7.05 

Corn  fodder,  dent,  all  analyses  

23.1 

1. 

.8 

14.6 

Corn  fodder,  dent,  in  tassel  

14.9 

1.1 

.8 

9.52 

Corn  fodder,  dent,  in  milk  

19.9 

1. 

.8 

13.64 

Corn  fodder,  dent,  dough  to  glazing.  .  .  . 

25.1 

1.3 

1. 

17.35 

Corn  fodder,  dent,  kernels  glazed  

26.2 

1.1 

.8 

16.74 

Corn  fodder,  dent,  kernels  ripe  

34.8 

1.5 

1.1 

22.48 

Corn  fodder,  flint,  all  analyses  

20.7 

1. 

.8 

13.53 

Corn  fodder,  flint,  in  tassel  

10.6 

.9 

.7 

6.89 

Corn  fodder,  flint,  in  milk  

15. 

.9 

.7 

10.39 

Corn  fodder,  flint,  kernels  glazed  

21. 

1. 

.8 

13.49 

Corn  fodder,  flint,  kernels  ripe  

27.9 

1.2 

.9 

17.84 

Corn  fodder,  sweet,  before  milk  stage.  .  . 

10. 

.8 

.6 

7.82 

Corn  fodder,  sweet,  roasting-ears  or  later 

20.3 

1.2 

.9 

13.38 

Corn  fodder,  sweet,  ears  removed  

21.5 

1. 

.8 

14.26 

Millet,  Hungarian  

27.6 

1.9 

1.1 

17.24 

Oat  fodder  

26.1 

2.3 

2. 

14.06 

Orchard  grass  

29.2 

1.7 

1.1 

15.81 

Rape  

16.7 

2.6 

1.7 

13.07 

Rye  fodder  

21.3 

2.1 

1.4 

15.99 

Sweet  sorghum  fodder  

24.9 

.7 

.4 

15.37 

Timothy,  before  bloom  

.24.2 

1.8 

1.1 

18.36 

Timothy,  in  bloom  

32.1 

1.3 

.8 

18.89 

Timothy,  in  seed  

46.4 

1.5 

1. 

26.36 

Wheat  fodder  

27.4 

2.8 

1.9 

18.75 

Green  Legumes 

Alfalfa,  before  bloom 19.9  3.5  1.9         9.2 

Alfalfa,  in  bloom 25.9  3.3  .8  11.5 

Alfalfa,  after  bloom 29.8  2.1  .3  11.1 

Clover,  alsike 24.3  2.7  .5  14.56 

Clover,  crimson 17.4  2.3  .6  10.83 

Clover,  red,  all  analyses 26.2  2.7  .7  15.87 

Clover,  red,  in  bloom 27.5  2.7  1.8  16.74 

Clover,  red,  rowen 34.4  3.3  2.2  17.3 

Cowpeas 16.3  2.3  1.7  10.42 

Peas,  Canada  field 16.6  2.9  2.1         9.78 

Soybeans,  all  analyses 23.6  3.2  2.4  12.53 

Soybeans,  in  bloom 20.8  3.  2.3  10.44 


ENERGY-PRODUCTION   VALUES 


453 


Green  Legumes — continued 

Soybeans,  in  seed 

Vetch,  hairy 


SILAGE 
Corn,  well-matured,  recent  analyses. 

Corn,  immature 

Corn,  from  frosted  ears 

Corn,  from  field-cured  stover 

Clover 

Cowpeas 

Soybeans 

Sugar-beet  pulp 

ROOTS,  TUBERS  AND  FRUITS 

Apple 

Beet,  common 

Beet,  sugar- 

Carrot 

Mangels 

Potatoes 

Pumpkin,  field 

Rutabaga 

Turnip 

GRAINS 
Cereal  Grains 

Barley 

Buckwheat 

Corn,  dent 

Corn,  flint 

Corn-and-cob  meal 89.6 

Corn  meal 

Oats 

Oat  meal 

Rye 

Wheat,  all  analyses 

Wheat,  winter 

Wheat,  spring 

Leguminous  Seeds 

Bean,  navy 86.6 

Cowpea 88.4 

Pea,  field 90.8 

Pea  meal 

Peanut  with  hull 

Peanut  kernel 

Soybean 


Dry 

,  Digestible  
Crude       True 

%     Net 
energy 

matter 

protein 

protein 

value 

Pounds 

Pounds 

Pounds 

Therms 

24.2 

3.1 

2.5 

12.7 

18.1 

3.5 

2.4 

11.95 

26.3 

1.1 

.6 

15.9 

21. 

1. 

.4 

11.96 

25.3 

1.2 

.6 

14.27 

19.6 

.5 

,3 

8.98 

27.8 

1.3 

.8 

7.26 

22. 

1.8 

1.1 

11.05 

27.1 

2.6 

1.5 

11.59 

10. 

.8 

.6 

9.32 

18.2 

.4 

.1 

15.92 

13. 

.9 

.1 

7.84 

16.4 

1.2 

A 

11.2 

11.7 

.8 

.5 

9.21 

9.4 

.8 

.1 

5.68 

21.2 

1.1 

.1 

18.27 

8.3 

1.1 

.6 

6.05 

10.9 

1. 

.3 

8.46 

9.5 

1, 

.4 

6.16 

90.7 

9. 

8.3 

89.94 

87.9 

8.1 

7.2 

59.73 

89.5 

7.5 

7. 

89.16 

87.8 

7.7 

7.2 

87.5 

89.6 

6.1 

5.7 

75.8 

88.7 

6.9 

6.4 

88.75 

90.8 

9.7 

8.7 

67.56 

92.1 

12.8 

11.5 

86.2 

90.6 

9.9 

9. 

93.71 

89.8 

9.2 

8.1 

91.82 

89.1 

8.7 

7.7 

91.66 

89.9 

9.2 

8.1 

91.41 

86.6 

18.8 

16.4 

73.29 

88.4 

19.4 

16.9 

79.46 

90.8 

19. 

16.6 

78.72 

89.1 

19.8 

17.2 

77.62 

93.5 

19.4 

16.9 

83.15 

94. 

24.1 

22.2 

109.04 

90.1 

30.7 

27.3 

81.29 

454 


APPENDIX 


Oil  Seeds 

Cotton  seed 

Flax  seed 

Sunflower  seed 

Sunflower  seed  with  hulls. 


. Digestible »     Net 

Dry  Crude  True  energy 
matter  protein  protein  value 
Pounds  Pounds  Pounds  Therms 


90.6  13.3  11.9  78.33 

90.8  20.6  19.2  83.17 

95.5  23.3  20.2  95.77 

93.1  13.5  11.7  92.49 


DAIRY  PRODUCTS 

Buttermilk 

Cow's  milk 

Skim-milk — centrifugal 

Skim-milk — gravity 9.6 

Skim-milk — dried 91.7 

Whey 

BY-PRODUCTS 
Fermentation  Industries 

Brewers'  grains,  dried 

Brewers'    grains,    dried,    below   25  per 

cent  protein 

Brewers'  grains,  wet 

Distillers'  grains,  dried,  from  corn 

Distillers'  grains,  dried,  from  rye 

Distillers'  grains,  wet 

Malt 

Maltsprouts 

Milling 

Buckwheat  bran 88.8 

Buckwheat  hulls 

Buckwheat  middlings 

Hominy  feed 

Rye  bran 

Wheat  bran 

Wheat  middlings,  flour 89.3 

Wheat  middlings,  standard 89.6 

Oil  Extraction 

Coconut  meal,  low  in  fat 90.4 

Coconut  meal,  high  in  fat 

Cottonseed  hulls 

Cottonseed  meal,  choice 92.5 

Cottonseed  meal,  prime 

Germ  oil  meal,  corn 

Linseed  meal,  new  process 

Linseed  meal,  old  process 

Palmnut  cake. .      


9.4 

3.4 

3.4 

13.32 

13.6 

3.3 

3.3 

29.01 

9.9 

3.6 

3.6 

14.31 

9.6 

3.1 

3.1 

15.43 

91.7 

34.4 

34.4 

103.91 

6.6 

.8 

.8 

10.39 

92.5 

21.5 

20.2 

53.38 

91.8 

18.7 

17.5 

50.93 

24.1 

4.6 

4.4 

14.53 

93.4 

22.4 

18.3 

85.08 

92.8 

13.6 

11.1 

56.01 

22.6 

3.3 

2.8 

22.05 

94.2 

15.8 

11.8 

87.82 

92.4 

20.3 

12.5 

72.72 

88.8 

10.5 

9.1 

30.59 

89.7 

.4 

? 

-7.69 

88. 

24.6 

20.8 

72.19 

89.9 

7. 

6.5 

81.31 

88.6 

12.2 

10.5 

79.35 

89.9 

12.5 

10.8 

53. 

89.3 

15.7 

14. 

75.02 

89.6 

13.4 

12. 

59.1 

90.4 

18.8 

18.3 

83.49 

92.3 

18.4 

18. 

100.31 

90.3 

.3 

? 

9.92 

92.5 

37. 

35.4 

93.46 

92.2 

33.4 

32. 

90. 

91.1 

16.5 

14.3 

83.88 

90.4 

31.7 

30.9 

85.12 

90.9 

30.2 

28.5 

88.91 

89.6 

12.4 

12. 

94.18 

MILK  PRODUCTION 


455 


• Digestible »  Net 

Dry  Crude  True  energy 

matter  protein  protein  value 

Pounds  Pounds  Pounds  Therms 
Oil  Extraction — continued 

Peanut  cake  from  hulled  nuts 89.3  42.8  41.4  93.55 

Peanut  cake,  hulls  included 94.4  20.2  19.5  42.57 

Soybean  meal,  fat  extracted 88.2  38.1  37.3  99.65 

Sunflower  seed  cake 90.  32.  29.1  88.87 

Starch  Manufacture 

Gluten  feed 91.3  21.6  20.1  80.72 

Gluten  meal 90.9  30.2  28.1  84.15 

Starch  feed,  dry 90.7  11.2  9.2  77.46 

Starch  feed,  wet 33.4  4.1  3.7  30.45 

Sugar  Manufacture 

Molasses,  beet 74.7  1.1  .  .  57.1 

Molasses,  cane  or  black  strap 74.2  1.  .  .  55.38 

Molasses  beet  pulp 92.4  5.9  3.5  76.28 

Sugar-beet  pulp,  dried 91.8  4.6  .7  75.87 

Sugar-beet  pulp,  ensiled 10.  .8  .5  9.32 

Sugar-beet  pulp,  wet 9.3  .5  .5  8.99 

Packing-House 

Dried  blood 90.3  69.1  68.6  68.12 

Tankage 

Over  60  per  cent  protein 92.6  58.7  55.6  93.04 

55-60  per  cent  protein 92.5  54.  51.1  83.58 

45-55  per  cent  protein 92.5  48.1  45.5  72.96 

Below  45  per  cent  protein 93.5  37.6  35.6  54.16 


4.  STANDARDS  FOR  MILK  PRODUCTION  AS  DEVELOPED 
BY  HAECKER,  SAVAGE,  AND  ECKLES 


PROTEIN  AND  TOTAL  NUTRIENTS  FOR  ONE  POUND  OF  MILK 


Per  cent 
fat  in 


2.5 

2.6 

2.7 

2.8 

2.9 

3. 

3.1 


Protein 
Pounds 
.07 
.039 
.0396 
.0402 
.0408 
.0414 
.042 
.0426 


Haecke 

Total 
nutrients 
Pounds 
.78 
.219 
.224 
.229 
.233 
.239 
.244 


.249 


Protein 
Pounds 
.07 
.0527 
.0535 
.0543 
.0551 
.0559 
.0567 
.0575 


Total 
nutrients 
Pounds 
.7925 
.2574 
.2629 
.2685 
.2743 
.2812 
.287 
.2928 


, Eckles , 

Total 

Protein     nutrients 
Pounds        Pounds 


*For  maintenance,  per  100  pounds 


456 


APPENDIX 


Per  cent 

,  Haecker  >    ,  Sa 

vage  < 

,  Eckles  , 

fat  in 

Total 

Total 

Total 

milk* 

Protein 

nutrients 

Protein 

nutrients 

Protein  nutrients 

Pounds 

Pounds 

Pounds 

Pounds 

Pounds   Pounds 

3.2 

.0432 

.254 

.0583 

.2987 

3.3 

.0438 

.26 

.0591 

.3055 

3.4 

.0444 

.265 

.0599 

.3115 

.0469   .285 

3.5 

.045 

.271 

.0608 

.3185 

3.6 

0456 

.276 

.0616 

.3243 

3.7 

.0462 

.282 

.0624 

.3312 

3.8 

.0468 

.287 

.0632 

.3369 

.051    .283 

3.9 

.0474 

.292 

.064 

.3428 

.056    .298 

4. 

.048 

.297 

.0648 

.3497 

4.1 

.0486 

.302 

.0656 

.3555 

4.2 

.0492 

307 

.0664 

.3612 

4.3 

.0498 

.312 

.0672 

.3671 

4.4 

.0504 

.317 

.068 

.3729 

4.5 

.051 

.322 

.0689 

.3787 

4.6 

.0516 

.327 

.0697 

.3842 

4.7 

.0522 

.331 

.0705 

.389 

4.8 

.0528 

.335 

.0713 

.3945 

4.9 

.0534 

.339 

.0721 

.3992 

5. 

.054 

.344 

.0729 

.4048 

5.1 

.0546 

.349 

.0737 

.4105 

5.2 

.0552 

.353 

.0745 

.415 

5.3 

.0558 

.357 

.0753 

.4209 

.048    .332 

5.4 

.0564 

.361 

.0761 

.4253 

5.5 

.057 

.366 

.077 

.4311 

.0587   .396 

5.6 

.0576 

.37 

.0778 

.4355 

5.7 

.0582 

.375 

.0786 

.4413 

5.8 

.0588 

.38 

.0794 

.4469 

5.9 

.0594 

.384 

.0802 

.4517 

6. 

.06 

.388 

.081 

.4572 

6.1 

.0606 

.392 

.0818 

.4619 

.072    .505 

6.2 

.0612 

.397 

.0826 

.4676 

6.3 

.0618 

.401 

.0834 

.4721 

6.4 

.0624 

.407 

.0842 

.4791 

6.5 

.063 

.41 

.0851 

.4835 

6.6 

.0636 

.415 

.0859 

.4882 

6.7 

.0642 

.419 

.0867 

.4926 

6.8 

.0648 

.423 

.0875 

.4984 

6.9 

.0654 

.428 

.0883 

.504 

7. 

.066 

.431 

.0891 

.5075 

*For  maintenance,  per  100  pounds. 


FEEDING  STANDARDS  457 

5.  FEEDING  STANDARDS 

The  feeding  standards  for  the  various  classes  of  farm 
animals  are  taken  from  Mentzel  &  Lengerke's  Landw. 
Kalender  for  1899.  They  are  intended  to  apply  to  ani- 
mals of  average  size  fed  under  normal  conditions.  They 
are  not  to  be  regarded  as  feeding  recipes,  but  are  to  be 
varied  according  to  circumstances.  Small  animals  should 
receive  proportionately  more  food  than  large  ones;  milch 
cows  in  proportion  to  the  quantity  and  richness  of  the 
milk;  growing  and  fattening  animals  according  to  the 
rapidity  of  increase  desired;  work  animals  according  to 
the  severity  of  labor,  and  individual  animals  according 
to  their  peculiar  needs. 

The  quantity  of  "dry  substance"  will  vary  according 
to  the  digestibility  of  the  ration,  with  no  harm.  It  is 
important  to  maintain  the  necessary  quantity  of  diges- 
tible dry  substance.  This  should  be  somewhat  more  if 
the  ration  has  a  larger  proportion  of  coarse  materials 
than  when  it  is  mostly  grain.  The  nutritive  ratio  may 
widely  vary  according  to  the  availability  and  price  of 
feeding-stuffs.  The  method  of  calculating  a  standard 
ration  is  explained  in  Chapter  XIX. 


PER  1,000  LBS.  LIVE  WEIGHT,  DAII/T 
Dry  /—Digestible  organic  substances— >  Nutri- 

sub-  Pro-     Carbo-  tive 

Kind  of  animal                    stance  tein    hydrates  Fat  Total  ratio  1: 

Lbs.  Lbs.       Lbs.  Lbs.  Lbs. 

1  .  Oxen— 

At  rest 18         .7         8.  .1  8.8  11.8 

Light  work 22  1.4       10.  .3  11.7  7.7 

Moderate  work 25  2.         11.5  .5  14.  6.5 

Severe  work 28  2.8       13.  .8  16.6  5.3 

2  .  Fattening  bovines — 

First  period 30  2.5       15.  .5  18.  6.5 

Second  period 30  3.         14.5  .7  18.2  5.4 

Third  period 26  2.7       15.  7  18.4  6.2 


458  APPENDIX 

PER  1,000  LBS.  LIVE  WEIGHT,  DAILY 
Dry  r-Digestible  organic  substances-^  Nutri- 

sub-  Pro-     Carbo-  tive 

Kind  of  animal  stance  tein    hydrates    Fat      Total    ratio  1: 

Lbs.  Lbs.      Lbs.      Lbs.       Lbs. 

3  .  Milch  cows — 

Daily     milk     yield     11 

pounds 25  1.6       10.  .3       11.9         6.7 

Daily    milk    yield    16^ 

pounds 27  2.         11.  .4       13.4         6. 

Daily     milk     yield     22 

pounds 29  2.5       13.  .5       16.  5.7 

Daily    milk    yield    27 V^ 

pounds 32  3.3       13.  .8       17.1         4.5 

4  .  Sheep — 

Coarse  wool 20  1.2       10.5         .2       11.9         9.1 

Fine  wool 23  1.5       12.  .3       13.8         8.5 

5  .  Ewes,  sucking  lambs 25  2.9       15.  .5       18.4         5.6 

6  .  Fattening  sheep — 

First  period 30  3.         15.  .5       18.5         5.4 

Second  period 28  3.5       14.5         .6       18.6         4.5 

7  .  Horses — 

Light  work 20  1.5         9.5         .4       11.4         7. 

Moderate  work 24  2.         11.  .6       13.6         6.2 

Severe  work 26  2.5       13.3         .8       16.6         6. 

8 .  Brood  sows 22  2.5       15.5         .4       18.4         6.6 

9  .  Fattening  swine — 

First  period 36  4.5       25.  .7       30.2         5.9 

Second  period 32  4.         24.  .5      28.5         6.3 

Third  period 25  2.7       18.  .4      21.1         7. 

10         GROWING  CATTLE 

Dairy  Breeds 

Live  weight 

Age  in  per  head 

months  Lbs. 

2-3 150. . .  .23  4.         13.         2.         21.  4.5 

3-6 300.... 24  3.         12.8       1.         16.8         5.1 

6-12.. . 500.  . .  .27  2.         12.5         .5       15.  6.8 

12-18 700.  .  .  .26  1.8       12.5         .4       14.7         7.5 

18-24 900 26  1.5       12.  .3       13.8         8.5 

Beef  Breeds 

2-3 165.  . .  .23  4.2       13.         2.         19.2        4.2 

3-6 330.  .  .  .24  3.5       12.8       1.5       17.8        4.7 

6-12 550.... 25  2.5       13.2         .7       16.4        6. 

12-18 750 24  2.         12.5         .5       15.  6.8 

18-24 935 24  1.8       12.  ,4       14.2         7.2 


FEEDING  STANDARDS 


459 


PER  1,000  LBS.  LIVE  WEIGHT,  DAILY 
Dry  ,— Digestible  organic  substances-^.  Nutri- 
sub-     Pro     Carbo-  tive 


Kind  of  animal 

stance 

tein 

hydrates 

Fat 

Total 

ratio  1 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Lbs 

GROWING  SHEEP 

Wool  Breeds 

Live  weight 

Ageiu 

per  head 

months 

Lbs. 

4-6 

60.  .. 

25 

3.4 

15.4 

.7 

19.5 

5. 

6-8.. 

75... 

.25 

2.8 

13.8 

.6 

17.2 

5.4 

8-11. 

85... 

23 

2.1 

11.5 

.5 

14.1 

6. 

11-15. 

90.  .. 

22 

1.8 

11.2 

.4 

13.4 

7. 

15-20. 

100... 

.22 

1.5 

10.8 

.3 

12.6 

7.7 

Mutton  Breeds 

4-6 

65 

26 

4.4 

15.5 

.9 

20.8 

4. 

6-8 

85   . 

.26 

3.5 

15. 

.7 

19.2 

4.8 

8-11. 

100  .  . 

24 

3. 

14.3 

.5 

17.8 

5.2 

11-15. 

120... 

.23 

2.2 

12.6 

.5 

15.3 

6.3 

15-20. 

150... 

.22 

2. 

12. 

.4 

12.4 

6.5 

GROWING  SWINE 

Breeding  Stock 

2-3 

45 

.44 

7.6 

28. 

1. 

35.7 

4. 

3-5 

100 

.35 

5. 

23.1 

.8 

28.9 

5. 

5-6 

.    .                         120 

.32 

3.7 

21.3 

.4 

25.4 

6. 

6-8.. 

175... 

.28 

2.8 

18.7 

.3 

21.8 

7. 

8-12. 

260.  .. 

.25 

2.1 

15.3 

.2 

17.6 

7.5 

Growing  Fattening  AnimaU 

2-3.. 

45... 

.44 

7.6 

28. 

1. 

35.7 

4. 

3-5.. 

110... 

.35 

5. 

23.1 

.8 

28.9 

5. 

5-6.. 

150... 

.33 

4.3 

22.3 

.6 

27.2 

5.5 

6-8.. 

200.  .  . 

.30 

3.6 

20.5 

.4 

24.5 

6. 

8-12. 

275... 

.26 

3. 

18.3 

.3 

21.6 

6.4 

460  APPENDIX 

6.  FERTILIZING  CONSTITUENTS  OF  AMERICAN 
FEEDING-STUFFS 

This  table  is  the  one  prepared  by  the  Office  of  Ex- 
periment Stations,  United  States  Department  of  Agricul- 
ture, and  published  in  the  Handbook  of  Experiment 

Station  Work,  Bulletin  No.  15.  phos  potas 

phoric  sium 

Moisture  Ash  Nitrogen     acid  oxide 

%  %  %            %  % 
Green  Fodders 

Corn  fodder 78.61  4.84  .41         .15  .33 

Sorghum  fodder 82.19  ..  .23         .09  .23 

Rye  fodder 62.11  .  .  .33         .15  .73 

Oat  fodder 83.36  LSI  .49         .13  .38 

Common  millet 62.58  .  .  .61         .19  .41 

Japanese  millet 71.05  ..  .53         .2  .34 

Hungarian  grass  (German  millet)     74.31  .  .  .39         .16  .55 
Orchard    grass    (Dactylis    glomer- 
ate)*      73.14  2.09  .43         .16  .76 

Timothy  grass  (Phleum  pratense)*     66.9  2.15  .48         .26  .76 
Perennial     rye     grass      (Lolium 

perenne)* 75.2  2.6  .47         .28  1.1 

Italian  rye  grass    (Lolium   itali- 

cum)* 74.85  2.84  .54         .29  1.14 

Mixed  pasture  grasses 63.12  3.27  .91         .23  .75 

Red  clover  (Trifolium  pratense) . .      80.  .  .  .53         .13  .46 

White  clover  (Trifolium  repens)  ..81.  .  .  .56         .2  .24 
Alsike    clover    (Trifolium    hybri- 

dum) 81.8  1.47  .44         .11  .2 

Scarlet   clover    (Trifolium   incar- 

natum) 82.5  .  .  .43         .13  .49 

Alfalfa  (Medicago  sativa) 75.3  2.25  .72         .13  .56 

Cowpea 78.81  1.47  .27         .1  .31 

Serradella  (Ornithopis  sativus)....     82.59  1.82  .41         .14  .42 

Soja  bean  (Glycine  soja) 73.2  .  .  .29         .15  .53 

Horse  bean  (Vicia  faba) 74.71  .  .  .68         .33  1.37 

White  lupine  (Lupinus  albus) ....     85.35  .  .  .44         .35  1.73 

Yellow  lupine  (Lupinus  luteus)*..      83.15  .96  .51         .11  .15 

Flat  pea  (Lathyrus  syhestris)* 71.6  1.93  1.13         .18  .58 

Common  vetch  (Vicia  sativa)* ...     84.5  1.94  .59  1.19  .7 
Prickly  comfrey  (Symphytum  as- 

perrimum) 84.36  2.46  .42         .11  .75 

Corn  silage 77.95  .  .  .28         .11  .37 

Corn  and  soja-bean  silage 71.03  .  .  .79         .42  .44 

Apple  pomace  silage* 75.  1.05  .32         .15  .4 

*Dietrich  and  Konig:   Zusamensetzung  und  Verdaulichkeit  der  Futtermittei. 


FERTILIZING  CONSTITUENTS 


461 


Moisture 


Phos-   Potas- 

phoric      sium 

Ash     Nitrogen     acid      oxide 


Hay  and  Dry  Coarse  Fodders 

Corn  fodder  (with  ears) 

Corn  stover  (without  ears) 

Teosinte  (Euchlxna  luxurians) . . . 

Common  millet 

Japanese  millet 

Hungarian  grass 

Hay  of  mixed  grasses 

Rowen  of  mixed  grasses 

Red-top  (Agrostis  vulgaris) 

Timothy 

Orchard  grass 

Kentucky  blue -grass  (Poa  pra- 
tensis) 

Meadow  fescue  (Festuca  pratensis) 

Tall  meadow  oat  grass  (Arrhena- 
thrum  avenaceum) 

Meadow  foxtail  (Alopecurus  pra- 
tensis)   

Perennial  rye  grass 

Italian  rye  grass 

Salt  marsh  hay 

Japanese  buckwheat 

Red  clover 

Mammoth  red  clover  (Trifolium 
medium) 

White  clover 

Scarlet  clover* 

Alsike  clover 

Alfalfa 

Blue  melilot  (Melilotus  cxruleus) . 

Bokhara  clover  (Melilotus  alba) . . 

Sainfoin  (Onobrychis  sativa) 

Sulla  (Hedysarum  coronarium) .  .  . 

Lotus  villosus 

Soja  bean  (whole  plant) 

Soja  bean  (straw) 

Cowpea  (whole  plant) 

Serradella 

Scotch  tares 

Ox-eye  daisy  (Chrysanthemum  leu- 
canthemum) 

Dry  carrot  tops 

Barley  straw 

Barley  chaff 


7.85 

4.91 

1.76 

9.12 

3.74 

1.04 

6.06 

6.53 

1.46 

9.75 

, 

1.28 

10.45 

5.8 

1.11 

7.69 

6.18 

1.2 

11.99 

6.34 

1.41 

18.52 

9.57 

1.61 

7.71 

4.59 

1.15 

7.52 

4.93 

1.26 

8.84 

6.42 

1.31 

10.35 

4.16 

1.19 

8.89 

8.08 

.99 

15.35 

4.92 

1.16 

15.35 

5.24 

1.54 

9.13 

6.79 

1.23 

8.71 

.  . 

1.19 

5.36 

.  . 

1.18 

5.72 

, 

1.63 

11.33 

6.93 

2.07 

11.41 

8.72 

2.23 

.  . 

.  . 

2.75 

18.3 

7.7 

2.05 

9.94 

11.11 

2.34 

6.55 

7.07 

2.19 

8.22 

13.65 

1.92 

7.43 

7.7 

1.98 

12.17 

7.55 

2.63 

9.39 

2.46 

11.52 

8.23 

2.1 

6.3 

6.47 

2.32 

13. 

. 

1.75 

10.95 

8.4 

1.95 

7.39 

10.6 

2.7 

15.8 

2.96 

9.65 

6.37 

.28 

9.76 

12.52 

3.13 

11.44 

5.3 

1.31 

13.08 

.  . 

1.01 

.54 

.89 

.29 

1.4 

.55 

3.7 

.49 

1.69 

.4 

1.22 

.35 

1.3 

.27 

1.55 

.43 

1.49 

.36 

1.02 

.53 

.9 

.41 

1.88 

.4 

1.57 

.4 

2.1 

.32 

1.72 

.44 

1.99 

.56 

1.55 

.56 

1.27 

.25 

.72 

.85 

3.32 

.38 

2.2 

.55 

1.22 

.52 

1.81 

.4 

1.31 

.67 

2.23 

.51 

1.68 

.54 

2.8 

.56 

1.83 

.76 

2.02 

.45 

2.09 

.59 

1.81 

.67 

1.08 

.4 

1.32 

.52 

1.47 

.78 

.65 

.82 

3. 

.44 

1.25 

.61 

4.88 

.3 

2.09 

.27 

.99 

*Dietrich  and  Konig. 


462  APPENDIX 

Phos-  Potas- 

phoric  slum 

Moisture  Ash  Nitrogen  acid  oxide 

Hay  and  Dry  Coarse  Fodders-               %  %  %  %  % 
continued 

Wheat  straw 12.56  3.81  .59  .12  .51 

Wheat  chaff 8.05  7.18  .79  .7  .42 

Rye  straw 7.61  3.25  .46  .28  .79 

Oat  straw 9.09  4.76  .62  .2  1.24 

Buckwheat  hulls 11.9  .  .  .49  .07  .52 

Roots,  Bulbs,  Tubers,  etc. 

Potatoes 79.75  .99  .21  .07  .29 

Red  beets 87.73  1.13  .24  .09  .44 

Yellow  fodder  beets 90.6  .95  .19  .09  .46 

Sugar-beets 86.95  1.04  .22  .1  .48 

Mangel-wurzels 87.29  1.22  .19  .09  .38 

Turnips 89.49  1.01  .18  .1  .39 

Rutabagas 89.13  1.06  .19  .12  .49 

Carrots 89.79  9.22  .15  .09  .51 

Grains  and  Other  Seeds 

Corn  kernels 10.88  1.53  1.82  .7  .4 

Sorghum  seed 14.  .  .  1.48  .81  .42 

Barley* 14.3  2.48  1.51  .79  .48 

Oats 18.17  2.98  2.06  .82  .62 

Wheat  (spring) 14.35  1.57  2.36  .7  .39 

Wheat  (winter) 14.75  .  .  2.36  .89  .61 

Rye "  14.9  .  .  1.76  .82  .54 

Common  millet 12.68  .  .  2.04  .85  .36 

Japanese  millet 13.68  .  .  1.73  .69  .38 

Rice 12.6  .82  1.08  .18  .09 

Buckwheat 14.1  .  .  1.44  .44  .21 

Soja  beans 18.33  4.99  5.3  1.87  1.99 

Mill  Products 

Corn  meal 12.95  1.41  1.58  .63  .4 

Corn-and-cob  meal 8.96  .  .  1.41  .57  .47 

Ground  oats 11.17  3.37  1.86  .77  .59 

Ground  barley 13.43  2.06  1.55  .66  .34 

Rye  flour 14.2  .  .  1.68  .85  .65 

Wheat  flour 9.83  1.22  2.21  .57  .54 

Pea  meal 8.85  2.68  3.08  .82  .99 

By-products  and  Waste  Materials 

Corncobs 12.09  .82  .5  .06  .6 

Hominy  feed 8.93  2.21  1.63  .98  .49 

Gluten  meal 8.59  .73  5.03  .33  .05 

Starch  feed  (glucose  refuse)  . 8.1  .  .  2.62  .29  .15 

*Dietrich  and  Konig. 


FERTILIZING  CONSTITUENTS 


463 


Moisture 


Phos-   Potas- 

phoric      slum 

Ash     Nitrogen     acid      oxide 


By-products  and  Waste  Materials — 
continued 

Maltsprouts 10.38 

Brewers'  grains  (dry) 6.98 

Brewers'  grains  (wet) 75.01 

Rye  bran . 12.5 

Rye  middlings* ! 12.54 

Wheat  bran 11.74 

Wheat  middlings 9.18 

Rice  bran 10.2 

Rice  polish 10.3 

Buckwheat  middlings* 14.7 

Cottonseed  meal 9.9 

Cottonseed  hulls 10.63 

Linseed  meal  (old  process) 8.88 

Linseed  meal  (new  process) 7.77 

Apple  pomace 80.5 

*Dietrich  and  Konig. 


12.48 

3.55 

1.43 

1.63 

6.15 

3.05 

1.26 

1.55 

.  . 

.89 

.31 

.05 

4.6 

2.32 

2.28 

1.4 

3.52 

1.84 

1.26 

.81 

6.25 

2.67 

2.89 

1.61 

2.3 

2.63 

.95 

.63 

12.94 

.71 

.29 

.24 

9. 

1.97 

2.67 

.71 

1.4 

1.38 

.68 

.34 

6.82 

6.64 

2.68 

1.79 

2.61 

.75 

.18 

1.08 

6.08 

5.43 

1.66 

1.37 

5.37 

5.78 

1.83 

1.39 

.27 

.23 

.02 

.13 

INDEX 


Abomasum,  the,  103. 
Absorption  of  food,  116. 
Accessories,  food,  193. 
Acids,  the,  80. 
fatty,  84. 
amino,  66. 

limiting  factor,  191. 
Age,  influence  of,  133. 

relation  to  meat  production,  428. 
Air,  carbon  in,  13. 
Albuminoids,  57. 
Alimentary  canal,  parts  of,  94. 
Alfalfa,  227. 
Amides,  66. 
Amylopsin,  109. 
Animal,  ash  elements,  23. 

bodies,   mineral   compounds  of, 

44. 

fats,  food  sources,  208. 
foods,  origin  of,  9,  266. 
growth,  chemical  elements  in, 

12. 

heat,  a  waste  product,  184. 
regulation  of,  183. 
source  of,  10. 
organism,   work  performed  by, 

162. 
production,       adaptability       of 

crops  to,  273. 
refuses,  270. 

size  of  in  relation  to  ration,  301. 
substance,  source  of,  10. 
Animals,  cruelty  to,  433. 
elements  in,  21. 
environment    and    treatment, 

431. 

factors  in  management  of,  425. 
fattening,     experiments    with, 

365. 

feeding  experiments  in,  366. 
food  needs  of,  364. 


Animals,  fattening,  rate  of  increase, 

363. 
selection   for   meat   production, 

427. 

young,  milk  for,  351. 
Anti-bodies,  85. 
Argon,  17. 
Ash    compounds,    distribution    in 

the  animal  body,  45. 
distribution  in  parts  of  plants, 

42. 

in  plants,  39. 

constituents,  influence  of  manu- 
facturing processes,  43. 
for  egg  production,  409. 
elements  in,  21. 
after  ignition,  39. 
in  blood,  46. 

elements  in  soft  tissues,  46. 
of   plants,    mineral    compounds 

in,  38. 

variation  in  plants,  40. 
variations  due  to  species,  40. 
Assimilation,  87. 

Bacteria,  89. 

intestinal,  110. 

in  digestive  tract,  92. 
Barley  feed,  250. 

Beef,  growth  in  production  of,  363. 
Beet,  sugar-,  molasses,  256. 

residues  from,  255. 
Beri-beri,  193. 
Bile,  the,  106. 

function  of,  107. 
Birds,  digestive  apparatus  of,  403. 

food  needs  of,  399. 

young,  rations  for,  413. 
Blood,  the,  138. 

ash  elements  in,  46. 

circulation  of,  142. 


DD 


(465) 


466 


INDEX 


Blood  corpuscles,  139. 

the  plasma,  140. 

vessels,  in  absorption,  115. 
Bovines,  maintenance  rations   for, 

314. 
Breakfast    foods,    residues    from, 

248. 

Breed,  influence  of,  133. 
Brewers'  grains,  251. 
Buttermilk,  268. 

Calcium,  19. 

Calorie,  definition  of,  165. 
Calorimeter,  respiration,  214. 
Carbohydrates,  the,  69. 

as  a  source  of  fats,  161. 

classification  of,  70. 

digestibility  of,  120. 

functions  of,  160. 

physiologically  economical,  186. 

regulation  of  use,  149. 

source  of  energy,  160. 
Carbon,  13. 

dioxide,  elimination  of,  147. 
Cattle  foods,  classification  of,  219. 
distinctions  in,  263. 
energy  values  of,  166. 
Cellulose,  78. 

and  gums,  digestibility  of,  121. 
Chlorine,  18. 

Coarse  foods  vs.  grains,  263. 
Collagen,  57. 
Colts,  feeding,  358. 

rations  for,  359. 
Cooking  foods,  128. 
Combination    of   nutrients,    influ- 
ence of,  131. 
Compounds,  classes  of,  26. 

classification  of,  27. 
Combustible    and     incombustible 

matter,  24. 
Combustion,  24. 
Corn,  as  silo  crop,  231. 
Cottonseed  by-products,  composi- 
tion of,  259. 

hulls,  257. 

kernels,  258. 

meal,  257. 
Cow,  the  general  purpose,  427. 


Cows,  dairy,  calculation  of  rations. 

333. 

feeding  standards  for,  327. 
practical  rations  for,  335. 
requirements  of,  331. 
selection  of,  426. 

Crops,    adaptability    to    environ- 
ment, 272. 

to  kind  of  production,  273. 
drying  of,  220. 
ensiling  vs.  field  curing,  233. 
forage,  classes  of,  220. 
harvesting  of,  222. 
influence  of  maturity,  223. 
for  swine,  386. 
high  productivity,  275. 
methods  of  preserving,  233. 
productive  capacity  of,  274. 
soiling,  276. 
value  not  proportional  to  yield, 

224. 

Curing    fodders,    losses    through, 
221. 

Dairy  by-products,  268. 

wastes,  as  food  for  pigs,  384. 
Dextrin,  78. 
Dextrose,  71. 
Digestible  nutrients,  in  the  ration, 

299. 

Digestibility,    as   basis   of   values, 
286. 

determination  of,  135. 

influence  of  age,  225. 

meaning  of,  122. 
Digestion,  87. 

artificial,  103. 

as  a  whole,  112. 

changes  in  food,  88. 

changes  in  stomach,  104. 

coefficients,  inaccuracies  of,  136. 

factors  influencing,  122. 

in  intestines,  113. 

stimuli  to,  111. 

stomach,  112. 

summary  of  changes,  114. 

work  of,  176. 
Digestive  fluids,  113. 
Di-saccharides,  72. 


INDEX 


467 


Drying  crops,  conditions  of,  220. 
Drying  fodders,  effect  of,  125,  221. 

Eggs,  composition  of,  407. 

Egg  production,  ash  constituents 

for,  409. 

Elements,  distribution  of,  27. 
Energy,  chief  source  of,  183. 
determination  of  165. 

metabolizable,  168. 
distribution  of  losses  of,  169. 
expended  in  feed  consumption, 

177. 

how  originated,  163. 
in  cattle  foods,  166. 
loss  from  food,  167. 
loss  in  gases,  168. 
maintenance,     distribution     of, 

312. 

measurement  of,  165. 
metabolizable,  167. 
estimates  of,  171. 
in  feeding-stuffs,  172. 
in  fodders  and  grains,  173. 
nature  of,  163. 
net,  174. 

calculation  of,  178. 
•    necessary  to  work,  163. 
uses  of,  151. 

requirements    by    growing    ani- 
mals, 349. 

stored  by  plants,  10. 
transformation  of,  164. 
values,  as  basis  of  valuation,  285. 
calculation  of,  212. 
net,  computation  of,  179. 
determination  of,  211. 
with  different  rations,  175. 
Enzyms,  85. 
action  of,  92. 
in  pancreatic  juice,  108, 
Ether-extracts,  84. 
Esophageal  groove,  99. 
Ewes,  feeding  of,  354. 
Extractives,  67. 

Fat,  milk-,  83. 
Fats  and  oils,  80. 

functions  of,  161. 


Fats,  digestibility  of,  121. 
from  carbohydrates,  161. 
in  grains  and  seeds,  81. 
milk-,  food  sources  of,  321. 
nature  and  kinds  of,  82. 
Fat  soluble  A,  194. 
Fattening  animals,  rate  of  increase 

363. 

Fatty  acids,  84. 
Feces,  constituents  of,  118. 
Feeding  and  watering,  influence  of 

frequency,  130. 
experiments    as    basis    of    feed 

value,  290. 

conclusions  from,  203. 
with  fattening  animals,  366. 
practical,  203. 

practice,  conclusions  from,  202. 
standards,  294. 
American,  329. 
Grouven's,  327. 
Kuhn's,  328. 

the  Wolff-Lehmann,  328. 
Wolff's,  328. 
Woll's,  329. 

stuffs,  classification  of,  265. 
commercial  by-product,     242. 
commercial  values  of,  282. 
home  supply  of,  304. 
misleading  terms  for,  264. 
physiological  values  of,  284. 
selection  of,  286. 
valuation  of,  281. 
valuation  by  method  of  least 

squares,  283. 
Feeds,  classification  of,  264. 

digestibility  of  various,  287. 
Fermentation,  intestinal,  110. 

results  of,  91. 
Ferments,  88. 
action  of,  91. 
conditions  of  growth,  80. 
definition  of,  89. 
organized,  89 

structure  and  distribution  of,  89 
unorganized,  92. 
Fertility  and  legumes,  276. 
Fibrinogen,  55. 
Fibroin,  57. 


468 


INDEX 


Fodders,  effect  of  drying,  221. 

losses  through  curing,  221. 

preserving  of,  126. 
Food,  absorption  of,  114,  116. 

appropriation   by   growing   ani- 
mals, 347. 

as  a  source  of  energy,  162. 

combustion,     measurement    of, 
213. 

compounds,     inter-relation     of, 

185. 

relation  to  the  digestive  pro- 
cesses, 119. 

economics,  factors  involved  in, 
420. 

effect    on    constitution   of  milk 
solids,  340. 

effect    on    the   flavors   of  milk, 
343. 

effect  on  the  proportion  of  milk 
solids,  339. 

general  uses  of,  151. 

influence    on    kind    of    growth, 
347. 

maximum  absorption  of,  117. 

needs  of  fattening  sheep,  373. 

relation  to  quality  of  the  horse, 
357. 

relation  to  production,  420. 

requirements  for  pork  produc- 
tion, 381. 

unit,  the,  418. 

use  of,  145. 

wetting,  128. 
Foods,  animal,  origin  of,  266. 

cooking,  128. 

influence  of  grinding,  129. 

influence  on  milk-fats,  341. 

kinds  for  poultry,  400. 
Forage  crops,  classes  of,  220. 
harvesting  of,  222. 
yield  at  maturity,  223. 
Fowls,     adaptability    of    various 
foods  to,  415. 

feeding  standards  for,  411. 

maintenance  ration  for,  412. 

salt  a  necessity  for,  410. 

supply  of  grit,  410. 


Galactose,  71. 

Gastric  juice,  the,  103. 

Gelatin,  57. 

Gelatinoids,    nutritive    value    of, 

192. 

Gliadin,  56 
Globulins,  53. 

animal,  55. 

plant,  54. 

serum,  56. 
Glucose,  93. 
Glutenins,  56. 
Gluten  products,  252. 
Glycogen,  77. 
Glyco-proteins,  59. 
Grain,  storage  of,  241. 
Grains  and  seeds,  240. 

coarse  food,  263. 
Green  versus  dried  fodders,  220. 
Grinding  foods,  influence  of,  129. 
Grit,  supply  for  fowls,  410. 
Growing  animals,  energy  require- 
ments of,  349. 

Growth,   effect  on  water-content, 
32. 

in  beef  production,  363. 

in  fattening  sheep,  372. 

influence  of  food  upon,  347. 

requirements  for,  346. 
Growth-promoting  bodies,  303. 
Gums,  the,  nutritive  value  of,  188. 

Hay  values,  Thaer's,  327. 

Heart,  the,  140. 

Haematin,  60. 

Hemi-celluloses,  77. 

Haemoglobin,  60. 

Hen,  constituents  of  the  body,  406. 

Hens,  laying,  effects  of  food  upon, 

402. 

rations  for,  412. 
Histones,  58. 
Hominy  feed,  251. 
Hordein,  56. 
Hormones,  85. 
Horse,  the,  a  machine,  164,  387. 

estimate  of  work  ration,  392. 

food  requirements,  390. 

maintenance  needs  of,  315. 


INDEX 


469 


Horse,  relation  of  food  to  quality, 

357. 

the  stomach  of,  104. 
work  performed  by,  388. 
Horses,     digestibility     of     coarse 

foods  by,  134. 
maintenance  food  for,  315. 

rations  for,  317. 
oats  as  food,  396. 
working,  nutritive  ratio  for,  395. 
rations  for,  397. 
source  of  the  ration,  394. 
Hydrochloric     acid     in     stomach 

digestion,  104. 
Hydrogen,  15. 
Hydrolysis,  72,  93. 

Individuality,  influence  of,  133. 

influence  on  energy  losses,  171. 
Intestinal  juices,  109. 
action  of,  113. 

tract,  changes  in  the  walls  of, 

116. 
Intestines,  the,  105. 

form  and  length  of,  105. 
Invertase,  93. 
Iodine,  19. 
Iron,  19. 


Katabolism,  fasting,  311. 

Keratins,  57. 

Knowledge,  sources  of,  201 


Lactase,  93. 

Lactose,  73. 

Lacteals,  function  of,  115. 

Lambs,  feeding  of,  354. 

grain  food  for,  355. 
Lecithins,  85. 
Lecitho-proteins,  60. 
Legumes  and  fertility,  276. 
Levulose,  71. 
Linseed  meal,  259. 

oil,  extraction  of,  260. 
Liver,  the,  149. 
Lungs,  the,  143. 
Lymphatic  system,  115. 


Maintenance  food  for  horses,  315. 

for  sheep,  317. 
measured  by  fasting  katabolism, 

311. 

needs,  computation  of,  313. 
investigations   concerning,    309. 

of  the  horse,  315. 
rations  for  bo  vines,  314. 

for  fowls,  412. 
Maize,  226. 

kernel,  the,  structure  of,  252. 
Maltsprouts,  251. 
Maltase,  93. 
Maltose,  73. 

Manufacturing     processes,     influ- 
ence on  ash,  43. 

Man's  relation  to  animal  life,  3. 
Mastication,  94. 
work  of,  174. 
Matter,  classes  of,  23. 
Meat  production,  relation  of  age 

to,  428. 

selection  of  animals  for,  427. 
Metabolism,    fasting,    use   of   nu- 
trients in,  312. 
M  eta-proteins,  61. 
Methane,  losses  through,  171. 
Milk,  266. 

cows',  composition  of,  319. 
effect  of  food  upon  flavors,  343. 
fats,  food  sources  of,  321. 
fats  in,  83. 

influence  of  food  upon,  341. 
for  young  animals,  351. 
of  several  breeds,  268. 
production,      protein      require- 
ments for,  325. 
production,  use  of  nutrients  in, 

323. 

proteins,  food  sources  of,  321. 
relation  to  food,  338. 
secretion  of,  320. 
solids,  effect  of  food  upon  con- 
stitution of,  340. 
effect   of  food   upon   propor- 
tions, 339. 

rate  of  formation  of,  322. 
substitutes  for  calves,  354. 
substitutes  for  swine,  385. 


470 


INDEX 


Milling  processes,  247. 

Mineral    compounds,    in    animal 

bodies,  44. 
in  ash  of  plants,  38. 
elements,  distribution  of  in  ani- 
mal body,  154. 
equilibrium  of  in  animal  body, 

154. 

functions  of,  152. 
relation  to  animal  structure, 

153. 

relation    to    tissue    develop- 
ment, 155. 
relation     to     elimination     of 

waste  products,  154. 
relation  to  muscular  control, 

155. 

relation  to  osmosis,  155. 
relation    to    vital    processes, 

152. 

supply  of,  156. 
Mono-saccharides,  70. 
Motive  power,  source  of,  11. 
Mouth,  the,  94. 

Muscular  activity,  relation  to  pro- 
tein, 183. 

control,  relation  to  mineral  ele- 
ments, 155. 

Mutton  production,  371. 
Myosin,  55. 
Myosinogen,  55. 

New  process  linseed  meal,  260. 
Nitrogen,  16. 

compounds,     relative     impor- 
tance of,  189. 
supply  of,  16. 
uses  of,  17. 
Non-nitrogenous     compounds, 

classification  of,  69. 
composition  of,  68. 
Non-proteins,  66. 
Nucleo-proteins,  58. 
Nutrients,    digestible,    calculation 

of,  297. 

energy  value  of,  212. 
energy  values,  166. 
functions  of,  151. 
how  oxidized,  145. 


Nutrients,  quantity  for  fattening 
sheep,  374. 

rate  of  oxidation,  146. 

use  in  fasting  metabolism,  312. 

uses  in  milk  production,  323. 
Nutrition,  laws  of,  197. 
Nutritive  ratio,  295. 

Oat  clippings,  250. 

grain,  the,  249. 

hulls,  248. 
Oats,  as  horse  feed,  359. 

for  working  horses,  396. 
Oil  meal,  259. 

meals,  the,  256. 

Oils,  methods  of  extracting,  257. 
Old  process  linseed  meal,  260. 
Omasum,  the,  102. 
Organic  and  inorganic  matter,   25. 
Osmosis,  relation  to  mineral  ele- 
ments, 155. 
Oxidases,  146. 
Oxygen,  14. 

uses  of,  15. 
Oxy-haemoglobin,  60. 

Palatableness,  292. 
Pancreatic  juice,  the,  123,  108. 

enzyms  of,  108. 
Pectin  bodies,  the,  78. 
Pellagra,  195. 
Pentosans,  the,  77. 
Pentoses,  the,  72. 
Peptones,  the.  62. 
Pepsin,  104. 

in  gastric  juice,  104. 
Phospho-proteins,  59. 
Phosphorus,  18. 

compounds,    relative    efficiency 

of,  157.  t 

Physiological  requirements,  294. 
Pig,  stomach  of,  104. 
Pigs,  dairy  wastes  for,  384. 

unwise  feeding,  382. 
Plant  ash,  elements  in,  21. 
Plans,  elements  in,  20. 

new  versus  old  species,  273. 
Plasma,  of  blood,  140. 
Poly-saccharides,  74. 


INDEX 


471 


Pork  production,  378. 

food  requirements  for,  381. 
Potassium,  19. 

Poultry,  kinds  of  food  for,  400. 
Preparation  of  food,  influence  of 

methods,  127. 

Preserving  fodders,  influence  of 
conditions  and  methods, 
126. 

Problems  in  feeding  animals,  5. 
Production,  relation  to  food,  420. 
the  unit  of,  419. 
values,  estimation  of,  181. 

relation  to  profit,  195. 
Proteans,  61. 
Protein  as  a  source  of  energy,  159. 

of  fats,  159. 
coagulated,  61. 
commercial,  336. 
content   as   basis   of  valuation, 

289. 

derivatives,  60. 
efficiency  from  animal  sources, 

408. 
foods,   no   single  one   essential, 

337. 

functions  of,  158. 
home  supply  of,  276,  336. 
how  determined,  48. 
importance  of,  47. 
physiologically  necessary,  186. 
relation    to    muscular    activity, 

183. 
relative  importance  overstated, 

326. 

requirements    for    milk-produc- 
tion, 325. 
sparers,  187. 

standards,  revision  of,  303. 
supply  of,  302. 
Proteins,  alcohol  soluble,  56. 
as  tissue  formers,  158. 
classification  of,  49. 
cleavage  products  of,  63. 
digestibility  of,  119. 
efficiency  of,  215. 
familiar  examples  of,  52. 
greatly  unlike,  49. 
glyco-,  59. 


Proteins,  lecitho-,  60. 

milk,  food  sources  of,  321. 

not  wholly  oxidized,  146. 

nucleo-,  58. 

phospho-,  59. 

phosphorus-bearing     synthesis 
of,  192. 

properties  of,  62. 

simple,  52. 

the  true,  50. 

relative  efficiency  of,  190. 

ultimate  composition  of,  51. 

unlike  constitution  of,  63. 
Proteoses,  62. 
Psychic  factor,  the,  111. 
Ptyalin,  98. 

Ration,  calculating  of,  296. 

influence    on    development    of 

swine,  383. 
and  quantity  of,  124. 
of  size  of,  171. 
on  quality  of  product,  304. 
insufficient,  correcting  of,  300. 
maintenance,  307. 
character  of,  307. 
for  bovines,  309. 
for  horses,  317. 
how  provided,  308. 
proportion  used  as  fuel,  160. 
the  manipulation  of,  429. 
the  quantity  of,  431. 
relation  to  size  of  animal,  301. 
selection  of,  305. 
uses  of  production,  308. 
Rations,  adaptation  of,  293. 

calculations  for  dairy  cows,  333. 
fattening,  selection  of,  369. 
for  laying  hens,  412. 
for  young  birds,  413. 
practical,  for  dairy  cows,  335. 
selection  of,  for  sheep,  376. 
Rennin,  in  stomach,  104. 
Respiration,  143. 
apparatus,  209. 
calorimeter,  214. 
object  of,  144. 
Reticulum,  the,  101. 
Rigor  mortis,  55, 


472 


INDEX 


Roots  and  tubers,  239. 
Rumen,  the,  100. 
Rumination,  102. 

Saccharose,  72. 

Saliva,  the,  97. 

origin  of,  97. 

properties  and  office  of,  97. 
quantity  excreted,  98. 
Salt,  effect  of,  129. 

a  necessity  for  fowls,  410. 
Sap,  31. 
Season  and  storage,  influence  of, 

131. 

Screenings,  247. 
Secretins,  85,  111. 
Sheep,    fattening,   food   needs   of, 

373. 
quantity     of     nutrients     for, 

374. 

nature  of  growth,  372. 
growing,  standards  for,  356. 
maintenance  food  for,  317. 
place  on  the  farm,  371. 
selection  of  rations  for,  376. 
Silage,  acidity  of,  230. 

cutting  and  shredding,  237. 
crops  for,  234. 
growth  of  corn  for,  236. 
Silo,  changes  in,  228. 

cleavage  of  proteins  in,  230. 
extent  of  loss  in,  231. 
filling  the,  236. 
importance  of  losses  in,  233. 
losses  in,  229. 
necessary  loss  in,  232. 
rate  of  filling,  237. 
Silos,  construction  of,  235. 
Skimmed  milk,  268. 
for  calves,  351. 
Sodium,  19. 

Soft  tissues,  ash  elements  in,  46. 
Soiling,    conditions    favorable    to, 

277. 

crops  a  necessity,  276. 
area  and  rotation,  280. 
selection  of,  278. 
the  economy  of,  277. 
Soil  moisture,  influence  of,  33. 


Species,  influence  of,  133. 

Spongin,  57. 

Stage    of    growth,    influence    of. 

127. 

Standards,  German,  for  fattening 
animals,  367. 

for  milk  production,  330. 
Starch,  manufacture  of,  253. 
Starches,  the,  75. 

rate  of  digestibility,  120. 
Steapsin,  108. 
Steers,    fattening,     rations    for, 

370. 

Stomach,  the,  99. 
Straws,  the,  239. 
Sugar-beet  pulp,  255. 
Sugars,  the,  74. 

simple,  70. 

Swine,    changes    in    production, 
379. 

character  of  the  growth,  379. 

feeding  of,  378. 

forage  crops  for,  386. 

influence  of  ration  on  develop- 
ment, 383. 

Teeth,  the,  95. 

Temperature,  the  critical.  185. 

regulation  of,  183. 
Therm,  definition  of,  165. 

Urea,  elimination  of,  147. 

Vitamines,  85,  193. 
Vitellin,  56. 

Wastes,  elimination  of,  146. 
Water,  28. 

content,  conditions  affecting,  34. 
measurement  of,  29. 
variation    in    animal    bodies, 

37. 

elimination  of,  147. 
functions  of,  152. 
hygroscopic,  29. 
in  feeding-stuffs,  34. 
in  living  plants,  30. 
in  the  animal,  36. 
physiological,  30. 


INDEX 


473 


Water,  proportion  in  plants,  31. 
relation  to  preservation  of  foods, 

35. 

Water  soluble  B,  194. 
Water-supply,    for    fowls,    neces- 
sity of,  408. 
to  plants,  33. 

Wheat,     composition     of     milling 
products,  246. 


Wheat,  grain,  structure  of,  243. 

offals,  243. 

the  milling  of,  245. 
Whey,  268. 
Work,  food  expenditure  for,  389. 

influence  of,  133. 

of  animal  organism,  162. 

Zein,  56. 


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Professor  L.  H.  Bailey,  of  Cornell  University. 

In  the  five  parts  into  which  the  book  is  divided  the  author  treats 
horses,  cattle,  sheep,  swine,  and  poultry,  and  each  is  discussed  with 
reference  to  breeds,  judging  the  animal,  feeding,  and  care  and 
management.  There  is  also  a  chapter  on  the  general  principles  of 
feeding.  Practical  questions  and  numerous  laboratory  exercises 
supplement  the  text  and  compel  the  student  to  think  through  each 
subject  as  he  proceeds.  The  book  is  extensively  illustrated.  Designed 
for  use  as  a  textbook,  it  is  also  well  suited  for  use  as  a  reference 
book  in  schools  in  which  time  limitations  make  it  impossible  to 
use  it  as  a  text. 

Manual  of  Farm  Animals 

A  Practical  Guide  to  the  Choosing,  Breeding,  and  Keep  of 
Horses,  Cattle,  Sheep,  and  Swine 

By  MERRITT  W.  HARPER,  Assistant  Professor  of  Animal  Husbandry 
in  the  New  York  State  College  of  Agriculture  at  Cornell  University 

Illustrated,  decorated  cloth,  12mo,  545  pages,  index,  $2.00 
RURAL  MANUAL  SERIES 

"The  work  is  invaluable  as  a  practical  guide  in  raising  farm 
animals." — Morning  Telegram. 

"A  book  deserving  of  close  study  as  well  as  being  handy  for 
reference  and  should  be  in  the  possession  of  every  farmer  interested 
in  stock." — Rural  World.  

THE  MACMILLAN  COMPANY 

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